Induction motor sevcon gen4 issue

Electric Motors and Controllers
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Inwo   10 kW

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Induction motor sevcon gen4 issue

Post by Inwo » Jan 06 2020 8:57pm

8kw induction motor runs fine using s6 80v controller in 2000lb vehicle.
Same motor runs great using s4 80v gen4 in <1000lb vehicle.

S4 in the heavy vehicle chatters harshly at low speed and high torque demand.
I don't know the proper term for this. Cavitation, cogging?

Turning the drive profile torque down to 60% works, but at high cost in acceleration.

It may be as simple as clipping on overcurrent. Although full throttle in torque mode is fine when over a couple thousand rpm.

A way to limit torque at low rpm may cover up the problem.

Lower performance is expected with the smaller controller, but not this extreme.

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www.recumbents.com   10 kW

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Re: Induction motor sevcon gen4 issue

Post by www.recumbents.com » Jan 07 2020 11:39am

It sounds like the controller is having a hard time staying in sync at lower RPMs. Is it using hall sensors to determine the motor phase?

Warren

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Inwo   10 kW

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Re: Induction motor sevcon gen4 issue

Post by Inwo » Jan 07 2020 11:53pm

No, it's an induction motor with ab sensor.
Same motor and programming works fine in s6.
Am I wrong to expect it to work with s4 at lower performance?

It may be hitting a hard current limit and clipping. I would expect it to lock out in that case.

I'm looking for a way to limit torque at low rpm. It runs fine cutback to 60% torque.
I can start in a reduced torque mode, then switch to 100% drive profile, with good results.
I'm looking into triggering drive 2 from low speed.

My dld does not seem to have a table that sets torque/rpm.

Does someone have a new file for an 8kw induction motor?

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Inwo   10 kW

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Re: Induction motor sevcon gen4 issue

Post by Inwo » Feb 07 2020 11:42pm

More sevcon induction motor questions.
What do you suppose Polaris is trying to accomplish with this slip map?
Extracted from 2012 Ranger 8kw 48v s6 gen 4. I am using this in another vehicle.
Log shows full throttle and torque. Performance is lacking. Less than 300amps under heavy load. 6000rpm limit. Not hitting drive profile limit. Limited by torque to 6000rpm and 30mph.
Attachments
ranger oem slip.gif
ranger oem slip.gif (23.26 KiB) Viewed 80 times
Last edited by Inwo on Feb 07 2020 11:50pm, edited 1 time in total.

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Inwo   10 kW

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Joined: Dec 13 2016 12:01pm
Location: SE MN. USA

Re: Induction motor sevcon gen4 issue

Post by Inwo » Feb 07 2020 11:45pm

Compare to this from a 72v e-zone 7kw s4 gen4 induction motor drive.
I have both files if someone needs them.
zone oem slip.gif
zone oem slip.gif (79.92 KiB) Viewed 79 times

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