# Using a sepex motor vs. a series?



## 67volts (Jan 13, 2009)

Can anyone tell me what the dissadvantage would be to using this motor as appossed to a series wound?

http://cgi.ebay.com/Electric-EV-DC-...ryZ42922QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


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## yarross (Jan 7, 2009)

67volts said:


> Can anyone tell me what the dissadvantage would be to using this motor as appossed to a series wound?
> 
> http://cgi.ebay.com/Electric-EV-DC-...ryZ42922QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


It will probably cost more, but for the same power rating, SepEx will have better (broader) torque curves. In fact, AC vector control turns AC motors into virtual SepEx motors, with separate armature and field current control, so you can regard SepExs as most flexible motor type.


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## major (Apr 4, 2008)

67volts said:


> Can anyone tell me what the dissadvantage would be to using this motor as appossed to a series wound?
> 
> http://cgi.ebay.com/Electric-EV-DC-...ryZ42922QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


Hi 67,

Guess it depends on what your plans are in regards to the controller. With a suitable controller, SepEx can offer advantages over the series motor, depending on the application.

major


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## 67volts (Jan 13, 2009)

major said:


> Hi 67,
> 
> Guess it depends on what your plans are in regards to the controller. With a suitable controller, SepEx can offer advantages over the series motor, depending on the application.
> 
> major


Can I use a regular curtis controller? Like a 72v 400amp curtis controller 1209b model?


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## major (Apr 4, 2008)

67volts said:


> Can I use a regular curtis controller? Like a 72v 400amp curtis controller 1209b model?


Hi 67,

Maybe on the armature only. If you hardwired the motor to a shunt configuration, and used a controller intended for series motors, you would end up with a weak field at low speed and start-up. Just what you don't want. So to use a series motor controller on a shunt or SepEx motor, you need to just use it for armature voltage control and then control the motor field with another device. And, using a controller intended for a series wound motor on the armature only is risky business. It may not work well because you have eliminated the motor series field from the circuit and the inductance that goes along with that.

Curtis and Sevcon make SepEX controllers for the V and I you mention.

Regards,

major


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## ice (Sep 8, 2008)

For me the most serious disadvantage of the SepEx motor is its cost which is largely used to the work involved with the commutator both to build and maintain.


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## major (Apr 4, 2008)

ice said:


> For me the most serious disadvantage of the SepEx motor is its cost which is largely used to the work involved with the commutator both to build and maintain.


Hi ice,

I have no idea what you're talking about. The commutator for an equivalent SepEx and Series motor would be the same. Could it be that you are referring to the fact that the higher voltage/power SepEx motors can require interpoles and comm coils whereas series motors can avoid this by brush advance? I use 48 volt SepEx motors and they are priced about the same as their series wound counterpart and require no additional maintenance.

Regards,

major


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## JRP3 (Mar 7, 2008)

major said:


> Curtis and Sevcon make SepEX controllers for the V and I you mention.


Alltrax as well. I think the main drawback with SepEx motors is fewer choices for higher voltage controllers.


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## ice (Sep 8, 2008)

Yup, I am referring to the higher voltage/power SepEx motors can require interpoles and coils. I wasn't able to expand what i really mean...Sorry!


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## Guest (Jan 15, 2009)

Zapi makes a controller that works for motors with interpoles and will do regen. Not SepEx but makes using Series motors with interpoles good for regen. I have an 11" Kostov with interpoles and a Zapi H3 controller both set for 144 volts and regen. : )


Pete : )




ice said:


> Yup, I am referring to the higher voltage/power SepEx motors can require interpoles and coils. I wasn't able to expand what i really mean...Sorry!


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## ice (Sep 8, 2008)

Hi gottdi,

About your H3 controller, how much is the supply voltage for that equipment...


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## Guest (Jan 16, 2009)

Supply voltage for the controller operations is pulled from within the controller after you hook up all the high voltage cables. I did connect the controller up to my car but I am only running 72 volts and this controller will work with 72 volts but you need to tell it first. Many controllers will just know you have put in less but this one needs to be programmed for your voltage pack. That is why I have been hunting for a console so I can program this thing. I have removed the cover and it is pristine within the controller. I actually don't think it was ever used. The guy I purchased it from decided to go with a Sparrow and no longer needed this big controller and motor. I purchased it from him for a future project. I am toning down my EV projects and trying to focus on my Ghia right now. The controller is right now set up for 144 volts system and since I only have a 72 volt system I was unable to test it. The Kostov I purchased with this works just fine and it too is set for 144 volts. They were actually a matched set. I'd sell the matched set including the taperlock, and motor mounts and extra motor parts and the controller for $2500 Shipping extra if needed. I have a copy of the manual for the controller that I can give you as well. One should have a programming console to tweek the controller but it is usable as it is now. This controller can be used as just a traction controller if you did not want to use the Regen function. If you do not have a motor suitable for regen then you would only use this as a traction controller but it is a 144 volt controller and 1000 amps. Pretty dam nice one too. Just use the traction setup for your standard 8" or 9" motor and you can go up to an 11" too. For all you guys wanting a controller for a big fat motor. 

For now the controller is up for grabs for $1000 shipping extra. Be glad to ship it for you. I may have a buyer for my motor here local. Maybe. 

Pete : )




ice said:


> Hi gottdi,
> 
> About your H3 controller, how much is the supply voltage for that equipment...


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## engineer_Bill (Jun 24, 2008)

I'm using SEP-EX , so far it is working great. 72V, Kelly controller with REGEN.


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## Guest (Jan 16, 2009)

Awesome, I like hearing that. What motor are you using? I am using the Military Starter/Generator and My Kelly SepEx is modified to run this type of motor. The more information I have the better. I now have a heat sink for my Kelly but it is not mounted yet. I have my controller programmed for the Regen function. One question! How does your Regen work? Take your foot off the throttle or do you have another throttle to power the braking function? I have a second pot for my Regen but how to hook it up properly in the Ghia or Buggy is what I am pondering right now. 

Pete : )




engineer_Bill said:


> I'm using SEP-EX , so far it is working great. 72V, Kelly controller with REGEN.


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## engineer_Bill (Jun 24, 2008)

FOr the REGEN switch I used the NC contact on the throttle active switch. I was initially concerned about feedback, controller sensing that as as error condition, etc..., but after I worked out the wiring issues it worked fine. I am still concerned that I don't always want REGEN when coasting, but I can always move the switch to the brake light switch or something if that becomes a problem. The Motor is a Raymond forklift motor


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## ice (Sep 8, 2008)

Oh yes, I think your right about the feedback concerns, would it harm the controller or other devices?


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## Guest (Jan 19, 2009)

The feedback he was referring to was that the controller was telling him he had things hooked up wrong. It was not a feedback of AMPS through the controller. The controller is programmable for many things. Wiring the controller is not as simple as it may look. Leave one thing out and the controller will give you a fault feed back indication and won't work until you rectify the issue. It is that simple.

Pete : )




ice said:


> Oh yes, I think your right about the feedback concerns, would it harm the controller or other devices?


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## ice (Sep 8, 2008)

Oh I see, thanks for the info...how come you know all these things?


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## Guest (Jan 20, 2009)

I pay attention to details. That detail does not always show in my work but I like to learn and to do that I need to listen and watch and read and ask questions. Been doing that all my life and I am also a speed reader. In High School we participated in a Beta program in 73 and 74 for the Evelyn Wood Speed Reading program. Get good and you are guaranteed 90 comprehension of all you read. Guaranteed. We were in the top reading courses and this was a perk for us. Damn glad I did that too. Excellent for technical reading. I love to learn new stuff. 

Pay attention to details. 

Pete : )



ice said:


> Oh I see, thanks for the info...how come you know all these things?


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## ice (Sep 8, 2008)

Wow, i wish i also had that knowledge and know-how. But i also like to learn new things, same as you.


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## raszpel (May 19, 2010)

major said:


> Hi 67,
> 
> Maybe on the armature only. If you hardwired the motor to a shunt configuration, and used a controller intended for series motors, you would end up with a weak field at low speed and start-up. Just what you don't want. So to use a series motor controller on a shunt or SepEx motor, you need to just use it for armature voltage control and then control the motor field with another device. And, using a controller intended for a series wound motor on the armature only is risky business. It may not work well because you have eliminated the motor series field from the circuit and the inductance that goes along with that.
> 
> major


What type of device would be well suited for this application on a SepEx motor?


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## bigmotherwhale (Apr 15, 2011)

posted in wrong thread


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## sammyleal (Aug 1, 2016)

Can I overvolt a sepex motor? This kind of motor allows brush timing advance? Thank you!


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## major (Apr 4, 2008)

sammyleal said:


> Can I overvolt a sepex motor? This kind of motor allows brush timing advance? Thank you!


Yes and yes. The armature voltage can be above rated or that which is on the nameplate. However the field will not tolerate excessive voltage for long before it overheats. Brush advance can be used to reduce arcing but its effectiveness will be dependant on field strength whereas in the series motor the field to armature strength ratio is constant.

major


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## mechano (Jun 1, 2015)

Hi engineerBill, can you give us more information about your conversion?
What size is your motor? power rating? rpm rating?
I think you use a kelly controller, which one is that?
what voltage-amps you are running?
Did you get benefits trying different field maps?

I am also planning to use a sepex motor, your inputs will be very helpfull.
my motor is this:











engineer_Bill said:


> FOr the REGEN switch I used the NC contact on the throttle active switch. I was initially concerned about feedback, controller sensing that as as error condition, etc..., but after I worked out the wiring issues it worked fine. I am still concerned that I don't always want REGEN when coasting, but I can always move the switch to the brake light switch or something if that becomes a problem. The Motor is a Raymond forklift motor


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