Addy said:minde28383 said:Can somebody explain me why two motors won't work if both 3 phase motors are on the same stator? And of course phase sequence is the same.
Do you now somebody trying to run such motor with one controller unsuccessful or successfully? Do you really know that it won't work?
I think it must work with one 3 phase controller.
Two motors can work together if their rotors are physically locked together and the electrical phases are exactly aligned. From what everyone is saying, it seems like the phases in your motor are not aligned. This is logical. Why would the manufacturer choose a 6 phase wiring setup if it would be easier to do a 3 phase winding? They have offset the phases for smoother torque delivery.
This is not necessary. A 3 phase motor could simply be driven with less current/power if you are trying to save energy - I don't think there would be much benefit to have separate windings for this. It is significantly more work to manufacture it with 6 phases and 6 wires.minde28383 said:Hi Addy,
My assumption is because manufacture would want to save energy and/or double power when needed thus having two motors inside one. When needed, both 3 phase motors kicks in, and when power is needed less then one 3 phase motor becomes idle. Idle motor drag can be canceled by controller.
If the phases are offset, if you tried to drive two offset phases at the same time, each phase would be pulling the magnets to a different place. They would be fighting each other. At best the motor would be very inefficient, if it even could spin at all.minde28383 said:Lets assume that phases are offset, but we don't know it yet, but lets assume it.
Why two 3 phase motors on the same stator can't be driven by one 3 phase controller? Does anybody truly understands it and can explain?
Addy said:If the phases are offset, if you tried to drive two offset phases at the same time, each phase would be pulling the magnets to a different place. They would be fighting each other. At best the motor would be very inefficient, if it even could spin at all.minde28383 said:Lets assume that phases are offset, but we don't know it yet, but lets assume it.
Why two 3 phase motors on the same stator can't be driven by one 3 phase controller? Does anybody truly understands it and can explain?
minde28383 said:"pulling the magnets to a different place"
Isn't it the whole idea of making movement.
If phases are one after another then it will drive forward, not fight. Why phases would fight each other. Don't know about efficiency, this is a whole other topic, but according my understanding the hub should run good with one 3 phase controller.
minde28383 said:Did little test but I doubt if this test can be trusted determining phase firing times.
At the beginning I thought that bulbs can show phase start times but now I think that if phase angle would be off by 30 and you still won't see difference looking to bulb turning ON/OFF.
Nevertheless both bulbs fire ON exactly at the same time.
Addy said:minde28383 said:"pulling the magnets to a different place"
Isn't it the whole idea of making movement.
If phases are one after another then it will drive forward, not fight. Why phases would fight each other. Don't know about efficiency, this is a whole other topic, but according my understanding the hub should run good with one 3 phase controller.
Pulling the magnets to a different place at a different time would make the motor spin. Pulling them to a different place at the same time would accomplish nothing except wasting energy.
Your understanding is incorrect, as everyone is trying to tell you. If you're so sure that we're all wrong and that you understand brushless motor commutation, do an experiment with your motor. Drive it with a 3-phase controller, with your double phases wired in parallel. Let us know how well that works.
minde28383 said:minde28383 said:Did little test but I doubt if this test can be trusted determining phase firing times.
At the beginning I thought that bulbs can show phase start times but now I think that if phase angle would be off by 30 and you still won't see difference looking to bulb turning ON/OFF.
Nevertheless both bulbs fire ON exactly at the same time.
flat tire said:Yes. Just plug them both into the controller. I don't understand why you still haven't tried this. A bad config WILL NOT blow the controller with a brief test at partial throttle. Do you not believe this? People here might do essentially the same thing several times as they try different phase combos in a motor with unknown phase / hall position. You will know immediately if the motor works.
Alan B said:Here's the for sale thread for a motor like this:
https://endless-sphere.com/forums/viewtopic.php?f=31&t=46898
The seller might have some advice for you.
Rewinding a hubmotor is a lot of work and there are many mistakes that can be made. There are threads here on doing that.
flat tire said:Since the answer to your question is staring you in the face let me just quote my last unacknowledged post.
flat tire said:Yes. Just plug them both into the controller. I don't understand why you still haven't tried this. A bad config WILL NOT blow the controller with a brief test at partial throttle. Do you not believe this? People here might do essentially the same thing several times as they try different phase combos in a motor with unknown phase / hall position. You will know immediately if the motor works.
flat tire said:Where do you live that you would rather rewind the motor (lol) than just get two controllers?
Alan B said:One of the advantages of the six pole motor is the reduced need for sinewaves, due to the overlapping three phases the ripple is considerably reduced even with trapezoidal controllers.
minde28383 said:Alan B said:One of the advantages of the six pole motor is the reduced need for sinewaves, due to the overlapping three phases the ripple is considerably reduced even with trapezoidal controllers.
It is very interesting point I had never heard or thought about it before. I mean - ... six phase, overlapping, ripple, reduced need for sinewaves...
These mid powerfull trapolized controllers are about 100usd each and 100 shipping so 300usd overall without VAT.
So for me it's either speding 300usd for two trapolized or getting second Sabvoton for also 300usd.
Depends on the phase angle difference. If it's 1 degree or something you might not even notice the difference. If it's larger you will see odd effects, including running fast in one direction but slow in another (phase advance/delay) reduction in torque (fields opposing each other) and unusual back-EMF's (could be dangerous for controllers.)minde28383 said:If phases are one after another then it will drive forward, not fight. Why phases would fight each other. Don't know about efficiency, this is a whole other topic, but according my understanding the hub should run good with one 3 phase controller.
Ohbse said:Glad you came to your senses! I have one of these motors, they're incredibly good compared to most other hubs. Two Sabvotons or Kelly controllers and you can pretty easily run 20kw.
billvon said:Depends on the phase angle difference. If it's 1 degree or something you might not even notice the difference. If it's larger you will see odd effects, including running fast in one direction but slow in another (phase advance/delay) reduction in torque (fields opposing each other) and unusual back-EMF's (could be dangerous for controllers.)minde28383 said:If phases are one after another then it will drive forward, not fight. Why phases would fight each other. Don't know about efficiency, this is a whole other topic, but according my understanding the hub should run good with one 3 phase controller.
Again depends on phase angle.minde28383 said:Danger of back-EMF I understand following way. Current is pushed to one phase but in the mean time another phase from another 3 phase motor is working as generator and generating electricity. Because controller is meant to work with three phase it might not block (gates open) current generated fed back to controller and possible have negative effect on controller itself?
That seems VERY unlikely. The most likely explanation is that their topology is the same, they are just phased differently. (Note - delta wound motors have two magnet wires, or sets of magnet wires, terminating in each phase wire. No other connections. Wye wound have a big "central connection" point with one magnet wire, or one set of magnet wires, terminating in each phase wire.)So neither I noticed odd effect nor it ran at all. And does it has anything to do with phase angles. Can sobedy explain why it might had happen?
A hint. Two 3 phase motors are winded differently. One - start, another - delta?
billvon said:Here's an experiment you might try. I assume this motor has Hall sensors, right? Move the Hall sensors around so that a "compromise" position is reached; an average between the two phases. The motor would likely run, albeit with much lower efficiency and odd torque characteristics.