# Helwig Red Top Split Brushes



## DIYguy (Sep 18, 2008)

I'm starting this thread to gather info and opinion on this product. These brushes are being used in the new Netgain motor design I believe. These brushes have a split design that is suppose to help with commutation. They also have a padded top (Red-Top) where the spring pressure is concentrated. I believe this is to help bounce and cushion for vibration/movement. I think they are recommended to be used with "increased" spring pressure (4 psi ??). It seems that these folks are conversant with advanced brush design in various applications. 

www.wmea.net/Commercials/*Helwig*.pps

http://www.helwigcarbon.com/products/carbon-brushes.html

http://www.helwigcarbon.com/images/casted brush holder promo.pdf



Claims are better brush life. Lower operating cost. Higher currents. Better commutation. I've also heard claims of higher voltage capability, but didn't read this on their website. 

Comments? 

Thanks,
Gary


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## Yabert (Feb 7, 2010)

Interesting subject.....

Higher voltage with same motor... hum! 
I waiting for more comments.

http://www.youtube.com/watch?v=YpR3hfL94fs


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## Bowser330 (Jun 15, 2008)

sounds excellent, how much are they?


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## DIYguy (Sep 18, 2008)

Bowser330 said:


> sounds excellent, how much are they?


Ya, I dunno. I sent a message to them. They don't sell direct, but have some reps/distribution. When I rebuilt my GE lift motor, I replaced the brushes and it was more than I expected at around $150. We'll see what these come in at.


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## Bowser330 (Jun 15, 2008)

Opps, skipped over how Netgain is using them on the warp motors, no wonder they can typically handle more current & voltage than the average, off the forklift, DC motor....


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## DIYguy (Sep 18, 2008)

I have some interesting feedback that I will share. First I want to link to this document covering many aspects of bush design including various compositions and their respective benefits. Also, troubleshooting pictures and just a wealth of great information with a lot of graphics.

http://www.helwigcarbon.com/images/tc2008.pdf


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## DIYguy (Sep 18, 2008)

I had several back and forth emails until I reached the right technical guy. Seems they were worried about us getting too much proprietary info. This was my last message to them.....

"Thank you for your reply. I (and other forum members) have no interest in learning your trade secrets and composition details. 

I want to know if I can purchase brushes from your company (based on info given) that are better suited to my application. I want to know what model number to ask for and how much they cost. I would also like to know what benefits I can expect in technical terms. 

I (and they) are interested to know if they can improve performance in general terms and if so, in what technical terms. Example, if you order model xyz split, red top brushes for applications utilizing "I" current levels and "E" voltage levels, u can expect improvements in "these" areas. (Like ability to handle 10% more voltage and current with better commutation. 

You already list different composition brushes in your literature and what the characteristics are. I just don't know if I should use only this data to select my own "best guess". I'm looking for general feedback on selection information. Is this not something you do????"

I received a great reply.......

"
Hello Gary,

We will be glad to assist you and thank you for the understanding. As you have seen on our website we have hundreds of different electrical carbon grades. Net Gain has used some of these grades successfully. We select the grades based on application information given. The key information we are looking for is running current, number of brushes per motor, voltage, speed and if possible spring force. We do make certain industrial size springs as well. And certainly can recommend products or spring force.

We will also inform you about the benefits of a particular grade or product over other. The electro graphite grades such as H49 and H60 are popular on high voltage EV applications. H60 works best from 50-80 Amps/sq-in current density range whereas H49 takes higher loads up to 100 Amps/sq-in. H49 also commutates better as well if there is electrical stress situation. For lower current densities below 60 Amps/sq-in and low voltages ranging from 24-90v graphite grade K254 is very popular. It also films well in low humidity and dry atmospheres where other grades struggle to film. Following is some additional information for your reference if needed.

Advantages of a multiflex red-top brush over a solid brush-

1. A multiflex brush has more points of contact compared to solid brush.
2. As more wires are used compared to solid brush, the wires are more flexible. 
3. We have used multiflex redtop brushes over decades to resolve problems.
4. A multiflex brush runs cooler and helps the commutation by preventing the circulating currents in high voltage and high current applications.
5. Two section Red-Top pad invented by Helwig is an Industry standard now. It acts as an insulator to prevent the current to the spring. And rubber section helps to dampen the vibrations.

Hope this information helps.
We thank you for starting the thread on our product. Please let us know if we can be of further service to you."


I will supply more details now about my application and see what is recommended. This is not a "one size fits all" selection process.


Regards,
Gary


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## Yabert (Feb 7, 2010)

Many thanks!

Very good information.
Please continue to give us details.


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## DIYguy (Sep 18, 2008)

Yabert said:


> Many thanks!
> 
> Very good information.
> Please continue to give us details.


My pleasure. I sent them a lengthy email with pics this morning. No reply yet.

Will advise when I get something. Did you look at the document on brushes? Did you see the various chemistries and their corresponding current handling and voltage drop info? I'm sure the ones high in silver are good....but also very expensive. They go up to over 90% silver! Yikes.... .lol


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## elektroboy (Jun 22, 2011)

Yes, very interesting. Thanks.
The ones with copper in it are also for high currents. I'm curious what they will advise.


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## DIYguy (Sep 18, 2008)

Here is some feedback on from Helwig, specifically on my original brushes and a few other things....

Hello Gary,

The brushes have current density of 34.1-90.9 Amps/sq-in at 160-170V. The peak load at acceleration is 227.3 Amps/sq-in on brushes. The original grade is 497 from our competition named Mersen (old name was Carbone). It is moly flake type grade and based on the properties of the grade it may struggle at higher voltages but could be a good grade up to 90v. Moly flakes helps for filming and lubrication. The film on comm was decent medium dark. How was the original grade performing? I am not sure about the new grade you are using now but it would be interesting to find the grade name or properties such as resistivity and hardness.

The brush face pictures were not available but if you see edge burning on the brush face then split design with red top will help. Please pull up the sleeve and see if you see any heat discoloration on the wire.

The top bevel will reduce the downward force of the spring a bit but might help position the brush against the rotation. The spring force should be 2.5 pounds to get 4.55 PSI at brush face. You need a force gage to measure this or send a brush card to us to measure the spring force. Spring force must be same on all brushes. One brush will always be slightly shorter than other due to polarity effect and in your case it is exaggerated due to the advance position (brushes out of neutral). Hope all this helps!!!


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## DIYguy (Sep 18, 2008)

I pressed them a bit to find out what Netgain uses..... reply below....

NetGain uses multiple grades but H49 and H60 are more popular. In this application I would recommend H49.

H series Electrographite..... "Electrographites are the most common grades used on modern equipment
with good performance at high voltages, high current densities and high
speeds. There is a wide range of characteristics within this category.
Most electrographite grades are capable of handling overloads well."


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## DIYguy (Sep 18, 2008)

elektroboy said:


> Yes, very interesting. Thanks.
> The ones with copper in it are also for high currents. I'm curious what they will advise.


The copper graphite do handle high currents, but are meant for lower voltages.


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## DIYguy (Sep 18, 2008)

So I pulled one pair of my replacement brushes (ones I have been driving on since rebuilding the motor) out and turns out that they have H100 stamped on them. This is apparently one of the better quality grades. It is comparable to Helwig's K254. They still recommend the H49 over it though.
Also, according to some pictures, they said my brushes showed signs of significant "electrical stress". (No wonder as I had my Soliton maxed out just before it blew up... and that was the last time I drove it...lol). He indicated that the split brush would help this situation significantly. The leading edge, about 1/3 of the face was quite shiny compared to the rest of the face. I'll load pics later....


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## Yabert (Feb 7, 2010)

So now?
Will you buy Helwig Red Top Split Brushes?

Canadian supplier?
Price?


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## DIYguy (Sep 18, 2008)

Yabert said:


> So now?
> Will you buy Helwig Red Top Split Brushes?
> 
> Canadian supplier?
> Price?


Here are a few pics of my brush gear and current H100 brushes as well as the original brushes.

What's next? Yes, I will get a set. They have a distributor in Brantford, Ontario... about 40 min from my house. You may need to talk direct to head office engineering though. They will give me a set for evaluation. 

I will get a quote for 10 sets, and let you know price.

I need to measure my spring force next.


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## ndplume (May 31, 2010)

Hey DIY Guy,
This thread went ... dead. Is there and update. I understand that the red top brushes make quite a difference.
I saw a group buy on the Helwig bruses for the 8" ADC. Did you start one for the 9" ADC?
NDP


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## DIYguy (Sep 18, 2008)

ndplume said:


> Hey DIY Guy,
> This thread went ... dead. Is there and update. I understand that the red top brushes make quite a difference.
> I saw a group buy on the Helwig bruses for the 8" ADC. Did you start one for the 9" ADC?
> NDP


Hey ND. 
My motor is a GE not ADC. I think this thread was the introduction of the Helwigs to this forum. It took maybe a year after for it to catch on. I did get a set of the red tops. Unfortunately, they didn't radius them so, since I had other plans for a different motor, I didn't put them in. I will use split red tops in my 13" though. 
Also, its not that difficult to radius them, just takes a bit of fiddling. Much easier with the motor on the bench.  remove old brushes. Get some 100 grit sand paper, wrap comm with grit facing out, install one pair of new brushes. . Lower on paper, and spin comm back/forth till shaped. Then u still need to run them for several days to seat/film.


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## ruckus (Apr 15, 2009)

Have folks checked out the EVTV testing which includes a Hellwig video showing exactly why the brushes are better? EVTV found much lower heat with higher rpm which amounted to greater efficiency. This has also been tested in an EV with the same results. I will be posting the temperature results as soon as the 8" bulk order is complete and they are installed.

http://www.evtv.me/
Testing vid 1: May 18th
Testing vid 2:May 25th

Cheers


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## DIYguy (Sep 18, 2008)

ruckus said:


> Have folks checked out the EVTV testing which includes a Hellwig video showing exactly why the brushes are better? EVTV found much lower heat with higher rpm which amounted to greater efficiency. This has also been tested in an EV with the same results. I will be posting the temperature results as soon as the 8" bulk order is complete and they are installed.
> 
> http://www.evtv.me/
> Testing vid 1: May 18th
> ...


Yes, I watched them when they were made. I watch pretty much all of them... although I do skip some of the lengthy verbiage... lol 
The improvement in efficiency noted will be different under driving loads, I'm sure. Still, this IS the critical part of a brushed motor and I'm surprised it never got more focus prior to this. (for EV and racing applications that is)


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## ruckus (Apr 15, 2009)

I think the racers are all over the Hellwig brushes. But racers tend to keep tech that gives them the 'edge' a secret. 

I think the word is out. 

The fact that Netgain switched over means they are undoubtedly better. The real-world gains have been tested and found to be somewhere around 12% better in terms of wh/mi. That also means 12% less heat which is my interest. 250F x .88 = 220F. Ahhhh, now that is better.  Ok, now get that blower on there...


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## somanywelps (Jan 25, 2012)

Do these work on kostovs?


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## major (Apr 4, 2008)

ruckus said:


> The real-world gains have been tested and found to be somewhere around 12% better in terms of wh/mi. That also means 12% less heat which is my interest. 250F x .88 = 220F.


Hi ruck,

I, in no way, want to enter into a debate about brushes. However I have to point out that your statements which are quoted above are ridiculous. There is no way that 12% improvement in vehicle energy consumption could be attributable solely to a change in brushes. That amounts about 1 to 2 kW savings for an average EVcar in normal type driving. Just isn't feasible.

And then you must realize that temperature does not equal heat or power. A difference of a couple of kilowatts on the comm and brushes would cause a lot greater temperature differential than 30ºF. Your equation makes no sense whatsoever.

Regards,

major


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## GizmoEV (Nov 28, 2009)

major said:


> There is no way that 12% improvement in vehicle energy consumption could be attributable solely to a change in brushes. That amounts about 1 to 2 kW savings for an average EVcar in normal type driving. Just isn't feasible.


While it is one data point you might want to see what Tim Catellier (http://evz3.blogspot.com/) found with a brush change. The one thing I question is that it came with a motor change too. The first Warp 9 had the old brush and the replacement had the new brush so I don't know if there were other factors influencing the results.

The brush tests done on EVTV weren't exactly scientific because the power output of the motor used wasn't kept constant. It was just left to free spin. Ironic as it may sound, when I drive my Gizmo full throttle, the faster it goes the lower the power use. This may have to do with the way the Sevcon SepEx controller is working but that is what I see. The faster spinning motor in the EVTV tests naturally lowered the current draw.

There is no question that the design and material make a difference. How much difference is the question. I wish I had a full size EV where I could test it my self. I would only change the brushes and note the difference.


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## LithiumaniacsEVRacing (Oct 9, 2010)

I have new brush holders and the red top brushes for my Warp 11" motors, I was going to wait to install because I am so behind, but after reading these posts I just might install them before racing.


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## LithiumaniacsEVRacing (Oct 9, 2010)

LithiumaniacsEVRacing said:


> I have new brush holders and the red top brushes for my Warp 11" motors, I was going to wait to install because I am so behind, but after reading these posts I just might install them before racing.


I would like to add, my brush holder kit comes with a set of “*Power Tabs*” these will eliminate the internal interconnections, power connection studs etc. and bring out a tab that is bolted directly to each of the brush holders. The “Power Tab” will protrude out from each of the “windows” in the end bell of each of my Warp 11’s. The power connection studs for the field coils will remain the same.


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## GizmoEV (Nov 28, 2009)

LithiumaniacsEVRacing said:


> I would like to add, my brush holder kit comes with a set of “*Power Tabs*” these will eliminate the internal interconnections, power connection studs etc. and bring out a tab that is bolted directly to each of the brush holders. The “Power Tab” will protrude out from each of the “windows” in the end bell of each of my Warp 11’s. The power connection studs for the field coils will remain the same.


So does that mean you have to connect externally to each set of brushes so you have to make your own jumper between the pairs of brush sets?


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## onegreenev (May 18, 2012)

Yes, That is exactly correct. But what it does is allow a fat connection instead of the typical skinny internal one. It allows for much better flow of those electrons. I love the idea. I added crossover cables to my Kostov but they are still internal but will carry more electrons with less resistance. 

With the power Ron's pumping it is very important.


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## ruckus (Apr 15, 2009)

Is that the Hellwig brush holder or a home brew? source? cost? 

Major, I agree with your skepticism. The only way to find out is to test them. I will do this. I have taken temperature readings using an infrared thermometer driving a specific speed and distance. I will change the brushes, repeat the drive, and record the temperature.

Any drop in temperature is an increase in efficiency because inefficiency IS the source of the heat.

If a motor is using 300 watts to drive along and the motor is 85% efficient that is 45 watts going to heat. Raise that to 89% and now only 33 watts are heat. The motor efficiency changed 4% but the heat changed 27%.

My only test parameters are heat and ability to handle amps without the 'kxkxkxk' sound. Right now the heat on long drives is 250F and the max amps are 700. Not real impressive.


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## major (Apr 4, 2008)

GizmoEV said:


> While it is one data point you might want to see what Tim Catellier (http://evz3.blogspot.com/) found with a brush change. The one thing I question is that it came with a motor change too. The first Warp 9 had the old brush and the replacement had the new brush so I don't know if there were other factors influencing the results.


Of course there were other factors. Tim does a nice job relating his experience. But that was far from a controlled test from which any valid conclusion can be drawn and the amount of power difference, again, is much greater than could possibly be attributable to brushes alone.



> The brush tests done on EVTV weren't exactly scientific because the power output of the motor used wasn't kept constant. It was just left to free spin.


Unfortunately I am not privileged to have a decent internet access to make it possible for me to view EVTV. But if you infer a no-load test by "free spin", then I don't see how any valid conclusion could be drawn.



> Ironic as it may sound, when I drive my Gizmo full throttle, the faster it goes the lower the power use. This may have to do with the way the Sevcon SepEx controller is working but that is what I see. The faster spinning motor in the EVTV tests naturally lowered the current draw.


Yes, of course a series (or SepEx controlled) motor draws less current (and therefore less power) as it speeds up. At a fixed voltage, the RPM decreases with load and vice versa. In your Gizmo, you see lower power use as the speed increases because the acceleration decreases. In a strictly controlled test, the higher speed would require more power in equilibrium conditions.




> There is no question that the {brush} design and material make a difference.


I don't disagree. But it is unreasonable to attribute some of these "test results" solely to the brushes.

major


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## DIYguy (Sep 18, 2008)

ruckus said:


> I think the racers are all over the Hellwig brushes. But racers tend to keep tech that gives them the 'edge' a secret.


They are now, but they weren't back at that time.


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