# Warp 9 inline?



## poprock (Apr 29, 2010)

Hi; this is a similar question to a previous one about a general dynamics 36v DC series inline between gearbox and differential. Would any damage occur if a DC series wound was turning at tailshaft rpm. without any load and the answer by Major and others was no. I tried this and the basic idea worked but obviously underpowered for my Toyota Dyna 1.5 ton in direct drive.. 
Now I am moving to purchase a Warp 9 and have the same question. Will it also freewheel in the drivetrain without damage, apart from bearing and brush wear ? If not, what motor will? Your helpful answers will be appreciated. Poprock.


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## major (Apr 4, 2008)

poprock1 said:


> Hi; this is a similar question to a previous one about a general dynamics 36v DC series inline between gearbox and differential. Would any damage occur if a DC series wound was turning at tailshaft rpm. without any load and the answer by Major and others was no. I tried this and the basic idea worked but obviously underpowered for my Toyota Dyna 1.5 ton in direct drive..
> Now I am moving to purchase a Warp 9 and have the same question. Will it also freewheel in the drivetrain without damage, apart from bearing and brush wear ? If not, what motor will? Your helpful answers will be appreciated. Poprock.


Hi rock,

You can do this. Nothing real bad will happen. But also, not much benefit. An electric motor at driveline speed will not be a good application. Too low RPM for the motor to be effective, which also means too low of a torque contribution from the electric motor to the rear axle to help much with acceleration. 

A commutator machine DC machine can be back driven unexcited without "much" negative effects. Brush wear will be a concern over the long haul. Brushes will wear at a greater rate when there is no current flow. This condition when existing for prolonged periods will strip the important film from the comm surface which then increases friction. Short durations will likely be o.k.

You would be better off putting a brushless motor in there. An induction motor being a better choice than one having PM. 

Also, I don't know your intent, but the electric contribution to the drive cycle will yield the most benefit during the transients rather than steady state. In other words, use the electric for accelerations and decelerations, not highway cruise. 

Best way to add an electric motor to the drive line would be:

Use a gear reducer to get the motor RPM greater than driveshaft which also increases electric torque contribution.

Use the electric for accelerations, and decelerations.

Go brushless.

Possible use a mechanical disconnect to clutch out the electric system and put it to sleep for constant speed operation like highway driving.

Personally, I don't think this is a wise project for the DIYer. You're talking about hybrid conversion to an existing ICE vehicle. Your chances of ending up with a better performing or economical vehicle are slim.

Regards,

major


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## poprock (Apr 29, 2010)

_Use a gear reducer to get the motor RPM greater than driveshaft which also increases electric torque contribution.

Use the electric for accelerations, and decelerations.

Go brushless.

Possible use a mechanical disconnect to clutch out the electric system and put it to sleep for constant speed operation like highway driving.

*Thank you major. Your suggestions are how I had the dc motor running. A 2:1 reduction with chain drive giving good acceleration with ICE but not much by itself. Obviously chain oiling ,wear and noise were issues, but it worked. Perhaps a brushless with a reduction drive belt as in aircraft conversions would be the way to go,as I am not aware of any clutch system as in A/c's that would be heavy enough to turn the 4.44 diff ratio with 12' WHEELS. Still thinking.*_


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