VFD causes motor stall under load

I am trying to make a shredder, but I am having problems with the VFD.

The motor is connected to a relatively small plastics shredder blades via a gear box.
If I attach it directly to 3-phase 380V, it shreds the material without hesitation.
The current clamp says it uses about 1.5-2A while doing so

However, when I use a VFD and throw in the material, the motor will slow down and stop completely.
No error codes, it just stops and the VFD puts out a steady 3.5-3.8A.

The VFD's I have used are:
-V70-1.5S2 (1.5kw)
-YL620-A (2.2kw)

These are the motor specs:


I have set all the parameters (frequency, voltage, current etc) to the correct amount or even higher.
But no results. The only thing that gives somewhat of an improvoment is setting control mode from 'vector' to 'vf'.
What could be the cause? Or better: what could be the solution

jessevdz said:

I am trying to make a shredder, but I am having problems with the VFD.

The motor is connected to a relatively small plastics shredder blades via a gear box.
If I attach it directly to 3-phase 380V, it shreds the material without hesitation.
The current clamp says it uses about 1.5-2A while doing so

However, when I use a VFD and throw in the material, the motor will slow down and stop completely.
No error codes, it just stops and the VFD puts out a steady 3.5-3.8A.

The VFD's I have used are:
-V70-1.5S2 (1.5kw)
-YL620-A (2.2kw)

These are the motor specs:


I have set all the parameters (frequency, voltage, current etc) to the correct amount or even higher.
But no results. The only thing that gives somewhat of an improvoment is setting control mode from 'vector' to 'vf'.
What could be the cause? Or better: what could be the solution

Click to expand...

The numbers from your motor when running don't add up to the specifications:

380 volts X 2 amps per leg X 1.7 = at least 1.3 KW being drawn by your motor when under load.

Not sure why the motor stalls when run by the drive, but if it does so the drive should trip off with an error code.

1500 rpm synchronous speed, 1380 slip speed at full torque . . . high slip motor.

What brand of drive?

Does the drive have an auto-tune feature?

Did you set the cos phi parameter?

Drive may have a non-trip setting where it tops out on max current, but continues to put out the set max current. Many have that to avoid the need for an operator to reset it. It may have an error code, but will not "trip".

The shredder may draw a peak over the setting, and the motor, being high slip, may not power through it unless it can draw a large overload temporarily. The VFD may not allow that overload.

Once the motor stalls, the VFD cannot supply a higher current than the limit, so it cannot "break the motor loose", and it is stuck in the stall condition.

The motor may be too small. Shredders have high peak torque requirements, and the motor may just not get through that. One solution is a flywheel, to help bust through without loading the motor too much. That might give startup issues due to inertia, but that can be dealt with.

BTW, the motor cannot take max current in the stall condition, because it is getting no cooling from the built-in fan. Only if it has a separate fan is that really allowable for more than a short time.

jessevdz said:

The VFD's I have used are:
-V70-1.5S2 (1.5kw)
-YL620-A (2.2kw)

Click to expand...

Those are crappy Chinese VFDs, which doesn't help matters, but your problem appears to be that those are 220V VFDs.

https://www.omc-stepperonline.com/download/VFD manual datasheet.pdf

https://bulkman3d.com/wp-content/uploads/2019/08/YL620-A-Inverter-Manual.pdf

That would certainly cause it. Assuming these are standard IEC motors, you would rewire them from star to delta to run on 220V line to line instead of 380V.

Thanks for the replies.

The motor was star wired by a colleague. After wiring it to delta, it worked fine!