# Any thoughts on Netgain Coverbands for WarP/Impulse 9?



## booksix (Aug 26, 2008)

Sorry I don't have input, but I'm also wondering how they'd keep water out (hit downpour on my way to work, LOTS of water!)


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## major (Apr 4, 2008)

john818 said:


> Just wondering how effective Coverbands are and under what conditions they're recommended.


Hi john,

Been meaning to address this for you. Here goes. The best way is to use some terminology from the NEMA motors, although the DC guys usually don't.

TENV = Totally Enclosed Non Ventilated. No air exchange inside to outside the motor. No fan external to motor. May or may not have internal fan (or rotor fins). Generally well sealed, but not submersible and not explosion proof.

TEFC = Totally Enclosed Fan Cooled. Same as above except has a shaft mounted external fan opposite drive end which has a shroud directing air over outside of motor frame. Very common for AC motors, rare for EV DC motors.

TEBC = Totally Enclosed Blower Cooled. An external blower forcing air over the motor which is still TE.

ODP = Open Drip Proof. Motor has opening(s) on the bottom which allows air exchange.

OFC = Open Fan Cooled. Motor usually has an internal shaft mounted fan which sucks air in one end and blows air out the opposite end.

OFV = Open Forced Ventilated. Motor uses an external blower which forces air into one end and out the other. Motor may or may not include an internal shaft mounted fan.

OFC and OFV may include provision for drip proof or ducting to keep water and splash out.

In forklift talk:

E = ventilated electrical components used on the truck, including motor.

EE = non ventilated, or totally enclosed electrical components.

EX = Explosion proof electrical components.

Now to your question. With these DC motors used for EVs, coverbands come in many varieties. Most common are the mesh or screen coverbands used for OFC. Solid coverbands are used for TE (Totally Enclosed) or type EE motors. A solid coverband with a duct or port is used for OFV with a mesh coverband at opposite end. This may include DP provision.

I personally think the forced ventilated solution is best for most EVs. Even if the motor is OFC where the internal fan pulls air thru the motor, forced ventilation helps. It will continue to cool the motor at low RPM, even zero. Also, a big plus for forced ventilation is that you can duct clean air thru the motor, keeping out road grit and salt spray.

Forced ventilation can increase the rating of the motor, so, depending on the duty cycle and motor, it can allow for the use of a smaller motor. It can also keep the motor temperature lower which makes for a more efficient motor and increases the insulation life, as well as bearings and brushes. Yeah, forced ventilation requires addition of a powered fan. It uses some energy and has some noise associated. You can cycle the fan, or blower, with a thermal sensor to mitigate this.

No pun intended, I'm a big fan of forced ventilation.

major


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## RKM (Jun 9, 2008)

John818,

I've been thinking of a similar arrangement for a Warp9. I have a mile of gravel to travel each time I leave home. Dust, water, snow and road debris are all a concern. I've thought the best option would be to use a cover band and force cool filtered air (use existing engine air filter) through the motor. I also intend to do a full belly pan for areodynamics and splash protection.

This is one issue that definitely favours TEFC AC motors. The proposed solution should be cheap insurance against motor damage.

Rob


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## DIYguy (Sep 18, 2008)

RKM said:


> John818,
> 
> I've been thinking of a similar arrangement for a Warp9. I have a mile of gravel to travel each time I leave home. Dust, water, snow and road debris are all a concern. I've thought the best option would be to use a cover band and force cool filtered air (use existing engine air filter) through the motor. I also intend to do a full belly pan for areodynamics and splash protection.
> 
> ...


Hey Rob,

I'm really warming up to this idea!  

Thanks Major... your explanations and info have been most helpful.

Gary


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## john818 (Aug 1, 2008)

Thanks for the discussion, everyone.

So, it seems like the Netgain Coverband would be great for keeping debris out, although no one really got too _deep_ into the water issue.  My main concern is cooling, and it seems like it works pretty well for that, too.

I assume the best way to force air would be with a small fan run off the 12v system. Any suggestions on flow capacity or would it depend on the application, for example the type of filter? Would we need to allow for a better DC/DC converter, or is the draw not significant?


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## major (Apr 4, 2008)

john818 said:


> I assume the best way to force air would be with a small fan run off the 12v system. Any suggestions on flow capacity


Hey john,

I recommend an automotive heater blower. Without the heater, of course Don't know the CFM, but that is what I've used. The more air the better, but that type of blower is pretty cheap and already made for automotive duty. If you get fancy with the duct work, you might want to run the cool air over the controller first and then thru the motor.

Regards,

major


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## booksix (Aug 26, 2008)

Do the coverbands seal well? I'm probably going to run lift motors and make my own bands with strips of foam insulation and a blower to keep rain/debris out... But now, where does the air come back out? Obviously on the other end of the motor, but what kind of an outlet setup would work?


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## major (Apr 4, 2008)

booksix said:


> Do the coverbands seal well? I'm probably going to run lift motors and make my own bands with strips of foam insulation and a blower to keep rain/debris out... But now, where does the air come back out? Obviously on the other end of the motor, but what kind of an outlet setup would work?


Hey Brett,

For the coverband, use sheet steel or aluminum. They end up fairly tight, but not "sealed". I guess you could use some type of high temperature gasket, but it is really unnecessary. Maybe someone could point you to a picture of an FV installation. I don't have one handy.

Regards,

major


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## booksix (Aug 26, 2008)

Thanks major. I was thinking I'd go with aluminum. I would appreciate any links anyone has to get me started.


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## john818 (Aug 1, 2008)

Might not be what you're looking for, and neither is installed, but here are two pics of coverbands. From the descriptions, I assume they're both factory Netgain bands, but I can't say for sure.

The first is on the first page of Netgain's site under "What's New!" The band is shown straight, not wrapped into the shape needed to fit on the motor.
http://www.go-ev.com/

The second is on Pioneer Conversions' motor page near the bottom. The band is shown bent round, as it would be when mounted.
http://pioneerconversions.com/Motors.html


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## booksix (Aug 26, 2008)

wow, that a small opening. What kind of blowers are you supposed to use with that?


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