# Aux Blower for Motor?



## major (Apr 4, 2008)

grayballs said:


> I intend to press the internal fan off , and machine away the guide vanes on a couple of motors, I have. The plan is to attach an external blower and control it's speed in the approximate inverse of the motors speed. I think the motor probably generates most of it's heat in the lower rpm ranges, but does most of it's natural cooling in the upper ranges.,,,, Plus I would like to control the brush dust,(filter?), rather than pull it through the motor.
> Anyone tried something similar? Opinions?


Hi balls,

Opinion? Yeah. Bad idea. But hey. It is your motor. Do what you want to it. You going to rebalance the armature after you remove the fan? And your assumption about heat and low RPM is incorrect.

Now I like the external blower cooling method and recommend it. But I'd leave the original shaft mounted fan alone. The few watts it takes to turn the fan are well worth it in regards to motor cooling. And at the higher speeds when you really do need cooling, that fan will likely work better than your blower.

For what it's worth 

major


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## grayballs (Aug 27, 2008)

Major;
I was hoping you would weigh in on this,, I value your opinions,,, especially when they involve DC motors.
Every use I've had for these motors has had them hanging out in the free moving air,,,,, this time that will not be the case. I guess I will re-think my ducting and cooling issues.
Thanks for the input.


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## JRP3 (Mar 7, 2008)

grayballs said:


> Plus I would like to control the brush dust,(filter?), rather than pull it through the motor.


Shouldn't the brush dust be blowing out the comm end, not being pulled through the motor?


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## major (Apr 4, 2008)

JRP3 said:


> Shouldn't the brush dust be blowing out the comm end, not being pulled through the motor?


Shouldn't the coolest air hit the comm and brushes first to minimize the brush dust produced?


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## JRP3 (Mar 7, 2008)

I don't know, does the air heat up that much when traveling the 10-16 inch length of the motor that it would make enough difference at the brushes? How heat sensitive are they? I really don't know, I just assumed the fans were setup to pull air in from the DE and blow out the CE.


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## grayballs (Aug 27, 2008)

The fans are centrifucal so they are pulling air thru the motors,,,,, that was the reason for my question. My twin motor install will shroud the outlet side, somewhat so I thought I'd try to make that the high pressure end forcing more volume through the smaller opening.
Major's point makes perfect sense,,(my reason for posting). I hadn't thought about the balance issue, although it is something I can address, but the air temp to the brushes is even more reason for it to flow towards the drive end.
In my case I think I have room to change the duct and allow for the shrouded area and still keep the dust from building up in the motor bay,,,, and augment the flow rather than redirect it. At least that is what I'm looking at, now.


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## Guest (Feb 27, 2010)

Keep the original fan or use a good blower. Take your compressor to your motor once and awhile and your good to go. Get some good hard brushes and you will stay cleaner. Blowers cool from the comm end to the drive end. My GE motor is like that. I use a VW heater blower from a 74 up VW Bus. It is a dual outlet squirrel cage blower and it is a high volume blower. Runs on 12 volts and takes little amps. Easy for the DC DC to power. I have a switch to turn it on or off. 

Pete


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## major (Apr 4, 2008)

JRP3 said:


> I don't know, does the air heat up that much when traveling the 10-16 inch length of the motor that it would make enough difference at the brushes? How heat sensitive are they? I really don't know, I just assumed the fans were setup to pull air in from the DE and blow out the CE.


Hey JR,

If the air thru the motor doesn't heat up, then it isn't doing much good, is it? How much? Get a motor running at rated RPM and rated (or overload) and feel the exit air. Noticeably warmer. Ain't going to burn the flesh off your hand, but quite warm.

As for brushes, they are in my mind the most heat sensitive component in the motor. Get those puppies too hot, which usually occurs at the contact surface, you cook the binder out of the carbon or graphite and then you get rapid dusting. Get the wires a little to hot, you cut the insulation life by a few hours. The brushes will get to you first.

Of course all this depends on the particular motor design, the duty cycle and the ambient conditions. And not to make lite of other motor components and heat, like the bearings. But overall, the brushes are in my mind the most heat sensitive. Afterall, they kinda sit out there with little contact to other massive parts which have larger radiating surface.

Now the direction air flow on self ventilated motors is up to the motor designer. And they come in both versions. I think the radial fan at the DE is the most common in the States. This accommodates insertion of the armature thru the frame from the DE without the need to remove the fan. But there are motors which use a radial fan outside the CEH and pull air in the DE. Kostov does this I think. This likely adds some cost to the motor over the other method. But apparently works for them.

As for brush dust in the motor, forgetaboutit. If there is enough to bother you, you got another problem. Deal with it. Normal motors should not dust much at all. And the accumulation of dust in the motor is of little consequence. The motor professional will clean it when he turns your comm at the brush replacement intervals, if you ever reach that point in the motor's life.

FWIW,

major


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## JRP3 (Mar 7, 2008)

Thanks for the info. Guess I just got hung up on the dust issue from the ICE days, dust in motor = bad


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## Plamenator (Mar 6, 2009)

Hello all,
We have been quite intesively testing forced air cooling methods in the past few months so I think I have some interesting data for you.
(there is actually a question about it in our FAQ section http://kostov-motors.com/faq/)
Aparently the shaft mounted fan does not consume "a few amps".
We have discovered that 9" fan by itself is 440W with probably 600-700W for 11".
While I am not a "ventilation" expert, I would think that any forced air system has to match these 440-700W or 40-60A at 12V which is not small.
When sellecting forced air cooling look for one at 5000rpm and with a blade that matches in size the original fan on the motor.
The most important factors for proper ventilation are:
-the power of the system (rpm and size of fan blade)
-location of air sucking: ideally it should suck air axially from the end of the motor, i.e. where the shaft mounted fan is, the latter being removed first.
-the piping from fan to motor: if above setup is not used, the least bended and shorter the piping is, the better.
Gottdi's centrifugal turbine is probably too weak.
We have tried with similar turbines at 3000rpm (20A) and motor duty cycle was reduced from 60 to 18min 
To conclude, the stock fan appears to be surprisingly effective and powerfull. Combined with its perfect location, it is very difficult to replace it. 
I have even been thinking of keeping the fan position where it is but cutting it from the main shaft and attaching it to a separate motor to spin it at 5000rpm+ regardless of traction motor speed. Unfortunatelly this will make the composition longer. Just imagine though using an electric bicycle controller on the separate fan motor ....
I would love to hear your opinion on the last idea.


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## Plamenator (Mar 6, 2009)

Major, what is CEH, the motor case?


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## major (Apr 4, 2008)

Plamenator said:


> Major, what is CEH, the motor case?


Hi Plamen,

CEH = Comm End Head, or the bracket which is fixed to the frame and typically holds the brush gear and rear bearing.

DE = Drive End, which typically has the output shaft and is connected to the load.

Regards,

major


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## JRP3 (Mar 7, 2008)

I think it would be better to look at CFM ratings than power draw. It may be possible to move the same amount of air with a more efficient design. However your testing seems to suggest that the motor mounted fan is fairly efficient so it may be difficult to improve upon it. Instead of of divorcing the fan from the motor and running it independently it might make more sense to add another external fan that added cooling when a certain temperature was reached and that could run when RPM's had dropped but the motor was still hot. You might be able to downsize the internal fan to improve efficiency for normal usage and then have the external fan kick in when temperatures increased. The extra fan could also help overcome ducting restrictions.


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## Guest (Feb 28, 2010)

> Gottdi's centrifugal turbine is probably too weak.


I will go hunt the CFM's of the blower motor I use. My motor is designed for a blower like this for it's cooling needs. The cover seals around the edges and the blower air is forced completely through to the other end. I could be that it needs more but then again I am sure you can only force so much through that 2" opening. So far it seems to be doing OK. I won't say great because it still seems to get pretty warm on a hard drive. Not screaming hot but pretty warm. I have that temp sensor in the motor but have no clue as to what the temp actually is. I think what is in the motor is more like a cut off switch rather than a temp sensor for a temp gauge. Anyway I will look into CFM's for the blower I am using. 

Pete


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## DawidvC (Feb 14, 2010)

Fans normally consume power to the cubed root of their speed - the faster you turn them the more power the more quickly you need for the fan. I mostly work on industrial 3phase motors, and most drive-controlled motors have forced cooling. This give optimum cooling at all speeds, of your motor, and keep the powerdraw for the fan constant.

If you want to use forced cooling, determine the maximum airflow (cfm) that you would need for your motor, and get a blower (not a fan) that give you at least that airflow, preferably more to compensate for losses in the system.

This would give you the opportunity to use a small drive to power the blower. You can then use the temperature of the motor to regulate the speed of the blower to optimise the cooling of your traction motor. This would give you substantial energy savings.

Regarding dust and other unwanted stuff in the motor, fit some kind of gause or filter over the inlet to the existing fan or the blower inlet. Carbon dust and dirt in the motor can be blown out by compressed air when doing your brush inspection.

Have fun.
Dawid


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## major (Apr 4, 2008)

Hello Plamen,

From your web site: CAN THE SHAFT MOUNTED STOCK FAN BE REPLACED BY SOME FORCED AIR SOLUTION?In principle it can be replaced but the standard fan sets the stakes quite high. We have performed a test with a 9" motor at 5600rpm with fan and without fan. The difference is the energy consumed by the fan - this turns up to be 440W (11" fan will probably be about 600W). A forced air solution will never be as effective as the shaft mounted fan. Therefore to match it one needs a separate ventilator with at least 500/700W rating respectively for the 9/11" motors.



Plamenator said:


> Aparently the shaft mounted fan does not consume "a few amps".


So if that 440 watts was on a 120 volt motor, that would be 3.7 amps, or a few amps in my book 

Now, yeah, 440 watts is power which is included in the input power to the motor and will factor into the efficiency for the motor. But also note that this 440 watts fan power is at 5600 RPM. Likely near the maximum speed for the motor. So at 3000 RPM, fan power is likely to require a few amps.

But let's use the 440 watts. When the traction motor is working at, say 20 kW, it probably is like 80 to 85% efficient. So you are getting that 440 watts to turn the fan at a great efficiency. Compare that to using a 12 volt blower to get the equivalent 440W fan power. At that power, the 12V motor will likely be around 60 or 65% efficient (just a guess). And you would have to include the DC/DC converter efficiency because 40 to 60 amps on the 12V system, you'll need one. Point is that powering the fan from the motor shaft is likely the most efficient means to get the cooling air at high motor speed and load.

The obvious downside to this method is the poor cooling effect from shaft mounted fans at low motor speed. And often times, low motor speed can be seen at high motor loading. So you do need cooling in this situation. This is why I like the combination of an external blower and shaft mount fan. You can use a reasonable power rated blower. And even control it with a thermal sensor to mitigate power consumption and noise. Yet retain the efficient shaft mounted fan for effective cooling at high power and high speed.

The other thing I like about the external blower is that it will pass cooling air thru the motor at standstill. And this is a condition often seen in EVs. I have witnessed "heat soak" on motors when run at heavy load and then suddenly turned off. So while running, good air is passing thru the motor scrubbing heat from the brushes, comm, windings and all the surfaces. Then this air stops. There is no longer power producing heat in the motor, but the hot components can no longer transfer the residual heat to the air steam. So, that heat is then conducted to cooler parts of the motor, like the housing and bearings possibly. You can actually see temperature rise in parts of the motor after shut down. The blower motor can reduce this effect considerably, even with just a modest air steam. So the motor will be cooler for you when the traffic light turns green and you punch it.

You mentioned the decrease in motor rating. 


> We have tried with similar turbines at 3000rpm (20A) and motor duty cycle was reduced from 60 to 18min


The other side of the coin, so to speak, is the motor temperature if run at the same duty cycle with the wimpy fan versus the robust one. One can deduce that the motor would be considerably hotter. And hotter motors will have higher resistance in the copper windings due to the resistivity increase. This means higher loss for equal loads. So by having effective cooling, the motor can be more efficient and offset (to some degree) the power required to turn the fan.

And cooler motors live longer 

Regards,

major


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## gor (Nov 25, 2009)

we've got radiator blown recently from shutting-off engine... (overheated)


in other thread -there been specs of various blowers, air-pumps, fans, - just for general idea what airflow(volume) & power it could take, though major factor, probably, would be actual airflow restriction)


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## gor (Nov 25, 2009)

hi, Plamenator, - since you worked on aircooling - could you show airflow on Kostov crossection?
thank you


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## DavidDymaxion (Dec 1, 2008)

Does it matter if you cool with 1 or 2 external fans? Just using one external blower bugs me a bit, as it would blow onto one side of the commutator but not the other. Would 2 (or 4) be significantly better?

My Kostov internal fan is just flat blades of metal. I have wondered how much efficiency might be gained if the blades had an airfoil shape?

One data point: A local EVer put on an electric blower on his EV, and says the motor is noticeably much cooler after hills now.


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## Plamenator (Mar 6, 2009)

major said:


> Hello Plamen,
> 
> 
> So if that 440 watts was on a 120 volt motor, that would be 3.7 amps, or a few amps in my book
> ...


3.7A is indeed small but I was referring to the same power at 12V which is the likely voltage of a separate cooling system. Can DC-DC converters supply both 12V and 24V at the same time? 24V will be much better.

When the motor is stopped, temperature usually continues to rise for about 10-15sec usually by 5-10C.

We have 12V motors that can do the job of forcing air. Their efficiency is about 75-80% - http://kostov-motors.com/tractionmotors/dcseriesmotors/framesize150mm/

I fully agree with you that a separate cooling system will be very beneficial - just do not see an easy way to do it being no expert at ventilation.

I also suspect that the motor will not run cooler.
We will simply re-rate it from 24kW to 30kW


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## Plamenator (Mar 6, 2009)

gor said:


> hi, Plamenator, - since you worked on aircooling - could you show airflow on Kostov crossection?
> thank you


Sorry but no.
We make DC motors, not blowers or fans.
Hence we have no idea how to measure that.


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## Plamenator (Mar 6, 2009)

DavidDymaxion said:


> Does it matter if you cool with 1 or 2 external fans? Just using one external blower bugs me a bit, as it would blow onto one side of the commutator but not the other. Would 2 (or 4) be significantly better?
> 
> My Kostov internal fan is just flat blades of metal. I have wondered how much efficiency might be gained if the blades had an airfoil shape?
> 
> One data point: A local EVer put on an electric blower on his EV, and says the motor is noticeably much cooler after hills now.


Well, the commutator turns so its temp will be uniform  but you are right that 2/4 fans will be better not least due to better cooling of stator windings (which do not turn ).
It is actually stator windings that overheat first in our motors and not the collector. WarPs should be the other way around due to lack of interpoles.
If you shape the blades, the fan will probably suck air differently CCW and CW? It will be an interesting experiment to get an axial fan but then you will need some free space behind the motor (where the auxiliary shaft is) for the air to escape.
Does anyone know of a company that sells only blades so we can mount different blades and see the effect?


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## JRP3 (Mar 7, 2008)

Plamenator said:


> 3.7A is indeed small but I was referring to the same power at 12V which is the likely voltage of a separate cooling system. Can DC-DC converters supply both 12V and 24V at the same time? 24V will be much better.


Why not use a fan that will run off pack voltage? Also, if you are only supplementing the stock fan then you don't need a fan that draws the same amount of power.


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## major (Apr 4, 2008)

JRP3 said:


> Why not use a fan that will run off pack voltage?


Hi JR,

This is done on some TEFC AC motors where the fan mounts on the rear of the motor and blows over the outside of the frame. They are small 3 phase, 230 or 460 volt fan motors. Fairly expensive choice.

For these external blowers guys use on EVs, most go with automotive fan assemblies like used for car heater blowers. Where can you get something like that rated for 120 Vdc or 144 or whatever your pack is?

On my old eJeep, a 96 volt job, it did have this type of blower with a PM motor rewound for 96 volts. It is one of a kind, I'm sure. And then slows considerably under load on the traction battery due to sag. So I'm real glad the traction motor still has the shaft mounted fan.

Regards,

major


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## gor (Nov 25, 2009)

gor said:


> hi, Plamenator, - since you worked on aircooling - could you show airflow on Kostov crossection?
> thank you[ / quote]
> quote=Plamenator;168928]Sorry but no.
> We make DC motors, not blowers or fans.
> Hence we have no idea how to measure that.


not sure if i understood you ... can you show crossection of kostov motor, and just put arrows (by hand), indicating air flow inside (and/or outside) of motor? (where air goes in, where out)
(airflow, created by built-in impeller (propeller, fan) - part of Kostov motor )
thank you


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## Plamenator (Mar 6, 2009)

I see now.
I thought you wanted me to calculate CFM of the stock fan.
Check if the attached picture is good for you.


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## gor (Nov 25, 2009)

thank you, Palmenator - like this
would be great to see under cower (crossection drawing) 
to see what what gap size, what additional can be done and what it wood take 
------
may be we can get away with electric fan, like on many radiators - constantly in (or depend of temperature), working from regular battery, running lights, etc...
but end result would still depend on particular case and particular design: if take any blower (gas,electric, etc) - put hand in front of it (restrict air flow out) - blower engine (motor) rpm would jump to red line w/o any load, blades would spin, moving nothing
than it would take air pump or compressor...


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## gor (Nov 25, 2009)

DavidDymaxion said:


> ...
> 
> My Kostov internal fan is just flat blades of metal. I have wondered how much efficiency might be gained if the blades had an airfoil shape?
> 
> .....


sure, it affects, but how much and to what extend...
first thing what everyone would do - it's increase blade size, angle, shape, blades number... since it directly affects rated specs - Kostov guys probably already tried that - and come to existing fan size (twice bigger fan blades - probably doesn't do any difference)
casing around the blades, blades configuration and shape - altogether does make difference in fan(blower) efficiency itself, but how it'll affect cooling system overall ... 
additional blower definitely should help on low rpm; blower(airpump) which builds pressure and forces it through motor - on any rpm


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## JRP3 (Mar 7, 2008)

major said:


> For these external blowers guys use on EVs, most go with automotive fan assemblies like used for car heater blowers. Where can you get something like that rated for 120 Vdc or 144 or whatever your pack is?


I thought some 120 volt AC fan motors might be able to run on pack DC voltage.


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## gor (Nov 25, 2009)

agnimotors specs doesn't give cooling system numbers:
"the limiting factor is the flow of cooling air through the motor and the continuous current at low voltages may be increased if ventilation is good. "

pms 120L:
Max. power at different motor-speed with aircooling at a min. airstream of 5 m/s

pmg 226:
"For extreme racing applications you maywish to add a stream of compressed air at thispoint ->2CFM@50PSI for cooling rotor in extreme high amperage situations "
-----
to just mowe air w/o peressure we looking at 1kw per 200-300 cfm


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## karmann eclectric (Mar 26, 2008)

I eliminated the internal fan, and am using two of the VW heater blowers, a later plastic-bodied Bosch, barely visible in this post. http://karmanneclectric.blogspot.com/2009/06/but-it-wasnt-done-was-it.html They're blowing into the com end, and there's a good stream coming out the drive end at all RPM. First blower latches on with the first energized potbox movement, and the second blower comes on when the field coils reach 70 degrees Celsius, and stays on, regardless of key position, until the motor cools. So far, I'm happy with their performance in road testing, but haven't gone more than a few spirited miles at a time. The only heat management issues have been in my clutch- the stock pressure plate couldn't handle the torque!


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## Plamenator (Mar 6, 2009)

I was thinking of attaching something like in the attachment to the Kostov 11" motors.
Not sure it will match the stock fan though given it is only 5A and at 24V.
And EBM probably would not sell just one 

Still, what are your opinions? 1750m3/h + 1700rpm of the fan.


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## gor (Nov 25, 2009)

fans just moving air and cooling only from outside? (outer shell)?
what going on inside? 
Would be great to see on the chart (drawing) or at least schematically where heat goes from the rotor, stator, how airflow directed


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## Plamenator (Mar 6, 2009)

Actually it is to be attached axially, replacing the current shaft mounted blade.
Air flow direction is not changed and kept as in my scetch above.
The black thing in the center is a brushless DC motor at 24V which can possibly be simply and cheaply controlled.
I just cannot determine if the specs of this centrifugal fan are up to the task of replacing the stock fan.


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## JRP3 (Mar 7, 2008)

Somehow you need to know how much air the stock fan is actually moving. There must be a way to calculate or measure what it's doing so you can compare it to others.


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## gor (Nov 25, 2009)

JRP3 said:


> Somehow you need to know how much air the stock fan is actually moving. There must be a way to calculate or measure what it's doing so you can compare it to others.


with water it would be easy- just pump from one reservoir to another
but how they doing it with air (cfm ratings)? what - taking their little pistols with propellers on the end - measuring wind velocity and multiplying on square(crossection)? dem... would be pain in ... our case...


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## GerhardRP (Nov 17, 2009)

JRP3 said:


> Somehow you need to know how much air the stock fan is actually moving. There must be a way to calculate or measure what it's doing so you can compare it to others.


How about this... 
Get everything to steady state. Measure the input power to the motor and calculate the heat being produced [and carried away by the air] using the motor efficiency. Measure the temperature rise of the air... all that is unknown is the mass flow rate of the air.
Knowing the motor efficiency is the hard part.
Gerhard


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## Guest (Mar 21, 2010)

grayballs said:


> The fans are centrifucal so they are pulling air thru the motors,,,,, that was the reason for my question. My twin motor install will shroud the outlet side, somewhat so I thought I'd try to make that the high pressure end forcing more volume through the smaller opening.
> Major's point makes perfect sense,,(my reason for posting). I hadn't thought about the balance issue, although it is something I can address, but the air temp to the brushes is even more reason for it to flow towards the drive end.
> In my case I think I have room to change the duct and allow for the shrouded area and still keep the dust from building up in the motor bay,,,, and augment the flow rather than redirect it. At least that is what I'm looking at, now.


If you look at your fan blades, in most cases you will see that some blades are square, and some have an angle to them. They've been filed to balance the rotor. You do NOT want to remove the fan blades. They're part of the motor balance.

That said, I advocate supplementary cooling fans. The air direction is a function of your motor direction. You have to determine which way your air flow is when driving forward. The fan can of course be reversed to accommodate that, usually by turning it around. 

Jack Rickard
http://evtv.me


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## major (Apr 4, 2008)

jrickard said:


> The air direction is a function of your motor direction. You have to determine which way your air flow is when driving forward. The fan can of course be reversed to accommodate that, usually by turning it around.


Hi Jack,

If you have an axial or propeller type fan on a motor shaft, then reversing the direction of rotation will reverse the air flow direction. However most motors used for EV traction have shaft mounted radial or centrifugal fans which blow air out in a radial direction from the axis of rotation. Radial fans blow outwards regardless of the direction of rotation. An example is the fan inside the Warp9. It is just inside the drive end head (DEH). Regardless of CW or CCW rotation of the Warp9, that fan blows air out of the DE of the motor while sucking air thru the motor from the comm end.

Reversing the fan (or turning it around) will not reverse air flow in either case.

Regards,

major


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## Plamenator (Mar 6, 2009)

I would not worry too much about the fan putting off balance the entire rotor, especially if the fan is made of plastic.
It has to be a very debalanced fan to do that.

Indeed a supplementary fan has to blow in the same direction as the shaft mounted one (whose direction Major pointed out). My problem with it is that such a supplementary fan will find a short cut. 
For example, in WarP's setup the supplementary fan will not suck air form the comm's end but from the vent openings diametrically opposite it.

Not a very good description but I hope you understand what I mean.


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## speedily (Mar 13, 2009)

Here's a setup that i've been working on for racing ,the intake (the red bite ) is 6'' OD , i plan to force the air in up to 50mph with a fan then turn it off and let speed do the rest, there should be more than enough air to keep the twins cool


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## Guest (Mar 22, 2010)

Plamenator said:


> I would not worry too much about the fan putting off balance the entire rotor, especially if the fan is made of plastic.
> It has to be a very debalanced fan to do that.
> 
> Indeed a supplementary fan has to blow in the same direction as the shaft mounted one (whose direction Major pointed out). My problem with it is that such a supplementary fan will find a short cut.
> ...


I was referring to the metal fan blades in the motor as being used for rotor balance. They are.

The vent openings are not a problem. Their is a shroud you can get for the Warp motor that replaces the screens with blank metal and provides a round duct hole for hose. You make a blower and route a hose into this duct.

My motor has no aux shaft and has some intake openings in the rear end. I can simply mount a fan so it blows air up the skirt of the motor.

Jack Rickard


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## Plamenator (Mar 6, 2009)

Actually I thought that you want to use the shaft mounted fan and the supplementary fan at the same time in which case the shroud is not good.
Running both fans together will also allow you to use the supplementary fan when the motor is not running to cool it down faster.

The set up that you describe is very unlikely to match the stock fan.


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## JRP3 (Mar 7, 2008)

I would think a shroud and ducted fan at the CE would push air towards the DE which would be un shrouded allowing the stock fan to still function.

Jack's setup is for an AC induction motor that pulls air in through the end, not side vents.


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## Plamenator (Mar 6, 2009)

JRP3 said:


> I would think a shroud and ducted fan at the CE would push air towards the DE which would be un shrouded allowing the stock fan to still function.
> 
> Jack's setup is for an AC induction motor that pulls air in through the end, not side vents.


 
Well, assuming WarP stock fan is at the DE, then the stock fan will have to suck air exactly from where the shroud is at the CE.
Having the shroud there would mean that it will try to suck air from the duct of the supplementary fan which is not big enough anyway...or at least this is how I imagine it.


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## Guest (Mar 22, 2010)

JRP3 said:


> I would think a shroud and ducted fan at the CE would push air towards the DE which would be un shrouded allowing the stock fan to still function.
> 
> Jack's setup is for an AC induction motor that pulls air in through the end, not side vents.


Your version is correct JRP. The Warp 9 pulls from the rear and blows out the drive end. The shroud covers the grills on the rear and you have the aux fan blow INTO the shroud through the provided coupling. You then have both fans and the motor does in fact run much cooler. 

I've had two different fan systems on the Warp 9 and wasn't really happy with either. But they did an excellent job cooling the motor. At the moment, I'm running it WITH the shroud but without the aux fan and it is getting hot.

I either have to put the grills back on or come up with another fan system.

The AC50 is much easier to deal with IF you do not have the aux shaft. You just bolt a fan over the end and you're done.

Jack Rickard
http://EVTV.me


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## JRP3 (Mar 7, 2008)

Plamenator said:


> Having the shroud there would mean that it will try to suck air from the duct of the supplementary fan which is not big enough anyway...or at least this is how I imagine it.


I suppose you could make it as big as you wanted. I guess you're worried that the ducting would be too restrictive for only the stock fan, but I'd think with the extra fan running you'd get extra air flow and better cooling over all, and that seems to be the case from those who have done it. Certainly you give up a bit of efficiency but I wouldn't think very much.


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## Dave Koller (Nov 15, 2008)

JRP3 said:


> I suppose you could make it as big as you wanted. I guess you're worried that the ducting would be too restrictive for only the stock fan, but I'd think with the extra fan running you'd get extra air flow and better cooling over all, and that seems to be the case from those who have done it. Certainly you give up a bit of efficiency but I wouldn't think very much.


You would think (there is where I gotta watch myself !) the efficiency might actually improve - well you are forcing air in the direction of flow so it would assist the rotation of the fan -hence a minuscule positive enforcement of rotation..  Or I am full of it.....


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## JRP3 (Mar 7, 2008)

And the energy to power the aux fan comes from where


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## Dave Koller (Nov 15, 2008)

JRP3 said:


> And the energy to power the aux fan comes from where


LOL the motor IS more efficient -(pause) - while we run the crap out of the battery ..
But we could let the perpetual motion crew show us how that's done  ..


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