Reverse Rotation for Novak Motors

[ta_man]

Has anyone figured out how to get the Novak Sensored Brushless motores to run in reverse (other than the Crawler and the reverse program of the XBR)? I want to run my HV-Maxx 6.5 in reverse rotation and the XBR just isn't up to that.

I know it is not as simple as switching two wires because of the sensors. Has anyone tried swaping sensor leads in the harness or maybe taking the motor apart and moving the hall effect sensors or the board? I asked Novak Customer Service this question a week ago and have received no response.

[kufman]

In theory you would have to swap two motor wires and two sensor wires. You would need an o-scope to figure which hall sensors match up with which power wires. You might also have to adjust timing of the motor by rotating the sensor board. I am not sure if they are in a neutral position or not. If you get it all correct, the controller would never know the difference.

[GSMnow]

I have not done it to a Novak, so this is a guess from working with industrial sensored motors. You need to swap the "A" and "C" phase wires. This is the easy part, they are the clearly labeled high current wires. Then you also need to switch the "A" and "C" sensor wires. Thanks to ROAR, the wire color and pin position is set by the rules. As per the 2007 ROAR modified motor rules, the phase "A" sensor is pin #4 and should be green. The phase "C" wire is pin #2 and should be orange. With some care, you should be able to pull the pin out of the plug and just switch those two. If it does not work, just put it back, it should not do any damage, it will just buck bad if it is wrong. Try it with no pinion gear first and try just a little throttle and make sure it is smooth from any position. On some industrial motors, the sensors were not always the same spacing as the rotor magnet, so it was trickier, but with just a 2 pole rotor and such a small space, I would hope they are sensing the rotor magnet directly with 120 degree spaced sensors, then it should work no problem. The controller will still drive A-B-C-A-B-C etc. but the motor will actually be doing C-B-A-C-B-A I hope that makes sense.

[ta_man]

Thanks for that info!

[CharlieS]

No amount of swapping wires or switching of sensor harness will make the motor run "correctly" backwards. I would strongly suggest against doing this.

The motor has timing built into it that moving the wires around does not take into account. I'm not even sure just moving the wires will work correctly, but I know it does not address any of the timing issues that will come up.

Thanks
Charlie

[jck_ahk]

I thought brushless motors had no "timing"?

[ta_man]

No amount of swapping wires or switching of sensor harness will make the motor run "correctly" backwards. I would strongly suggest against doing this.

The motor has timing built into it that moving the wires around does not take into account. I'm not even sure just moving the wires will work correctly, but I know it does not address any of the timing issues that will come up.

Thanks
Charlie

So how do the XBR and Crawler controllers do it? Do they "back out" the timing?

If Castle ever manages to finish the software update for running Novak motors maybe I will just use a Mamba Max with my HV 6.5.

Anybody got a Novak motor with burnt out windings they want to sell cheap? I'll rewind it and then see what can be done with extensive fiddling.

[kufman]

I have been using the Mamba Max controller on my novak 10.5 and 8.5, and it works pretty good. If you are just messing around and bashing, the mamba seems to work just fine on the novak motors. The only problem I have seen is at startup, but it isn't that bad. It isn't nearly as bad as my old Hacker controller on any motor I tried. If you have a descent amount of slop in your drive train, the mamba will work even better since it only takes a couple revolutions of the motor for the controller to lock on. My e-maxx has plenty of slop for this to occur. My XXX-4 does not, but works fairly well anyway.

[ta_man]

I have been using the Mamba Max controller on my novak 10.5 and 8.5, and it works pretty good. If you are just messing around and bashing, the mamba seems to work just fine on the novak motors. The only problem I have seen is at startup, but it isn't that bad. It isn't nearly as bad as my old Hacker controller on any motor I tried. If you have a descent amount of slop in your drive train, the mamba will work even better since it only takes a couple revolutions of the motor for the controller to lock on. My e-maxx has plenty of slop for this to occur. My XXX-4 does not, but works fairly well anyway.


I want to use an HV-Maxx 6.5 in a HPI MT2 conversion. Since the 6.5 has the sintered rotor, maybe it will be worth trying out. The MT2 has dogbones from the center slipper to the diffs at each end and there is some slop in the outdrives that go to the wheels. So it just might work. Thanks for that info.

[ta_man]

I thought brushless motors had no "timing"?
To answer your question, it appears that Novak motors do have timing.

I had one apart to change rotors just now and I looked closely at the circuit board in the back that has the Hall Effect sensors. They were not lined up in the center of the stator poles but were offset. So that consitutes timing.

Sometime soon I'm going to take one completely apart and see if there is enought freedom of motion that I can move the timing ring to get the sensors offset the other way. That would probably mean enlongating the holes in the circuit board but that may not be possible if there are traces in the way.

[CharlieS]

I think all motors can have timing.

In a Sensored system it can be in the motor, "or" in the ESC.

In a sensorless system it's in the ESC only.

The XBR and the Crawler have software provisions to offset for the timing in the motor so it will run the same both ways. :)

Sorry for the delay.

Thanks
Charlie

Don't forget, as easy as it is to post on a forum, you can ALWAYS email us direct for answers.
Charlie@teamnovak.com
tech@teamnovak.com
cs@teamnovak.com

[kufman]

Reminds me of running fixed endbell stock motors. Seems like a silly way to build modified motors.