I decided on the ADC FB1-4001A motor which I order from Cloud Electric and have already received.

Potential Motors

Advanced DC FB1-4001

  • 28.5 HP continuous, 100 HP peak (@144V)
  • 9.1 inches
  • Comes in a single shaft and dual shaft version

Netgain Warp 9

  • 70 HP @ 120V (435A)
  • V range 150-160, max 170
  • 9.25 inches
  • dual shaft (I think)
  • 143 lbs
  • company site

Netgain Impulse 9

  • 63 HP @ 120V (435A)
  • V range 150-160, max 170
  • 9.25 inches (mounting same as ADC 8")
  • dual shafts
  • 133 lbs

Threads about difference between Netgain and ADC:

D&D ES-31

  • company site
  • appears to be lower power than the above
  • have to contact company for specs
  • Update:  Bill contacted D&D, they say that have no suitable motor


There seem to be several common coupling techniques.  First, it will depend on clutch vs. clutchless.  I think that we have pretty much decided to go clutchless for this project, so I will focus on those couplings.

All of the following info is what I have read from various conversion blogs and from EV info sites.

Coupler with transmission shaft spline socket

This style seems to be a one piece coupling (or maybe more if a taperlock).  One end attaches to the motor shaft.  I haven't seen much detail about how the motor shaft attachment is made, but it appears that at least some of the time it is using some kind of key on the shaft.  This coupler is either machined from scratch or adapted by machining part of an existing coupling.  The splined "socket" that is in the center of a clutch disk is removed from the clutch and fitted into one end of the coupler and welded in place.  Here are some sites:

Coupler with modified clutch disk

This style uses a modified clutch disk bolted to the coupler.  The clutch disk is modified such that only the inner part of the disk, the part with the springs remains.  This is bolted to the coupler so that the springs still do their job of absorbing jolt in the coupling when the motor speed changes.  Here are some sites that show this coupling method:

I've seen a couple comments on forums saying that the springs either weren't needed or a bad idea, but no explanation that I have seen so far.

Miscellaneous Coupler Info Sites

Coupler Attachment to Motor

It appears to me that the strongest consensus on attaching the coupler to the motor is by using a "taperlock" hub.  Second seems to be using a keyway and key.  Seems to be a pretty strong consensus that couplers using set screws is a bad idea.

Though many thread mention "lovejoy" connectors, I have also seen a lot of comments that say these should not be used for EV because they are not up to the job and will be destroyed.

Forum thread about taperlock couplers.