Huanyang vfd puts out 175v instead of 220v

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Sblack

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as the title suggests this vfd runs fine but puts out only about 75% of the proper voltage. To make things interesting he included manual is only in Chinese! Why do they even bother? There is a table of parameters and it shows units and default values and from that I managed to change the frequency to 60 from 50 and speed up the acceleration. So the thing does work. But I can’t imagine why it would put out such an odd voltage.
it is a zw g2 2t 3, whatever that means. It says on the case that it outputs 220v at 3 kw. Any idea what parameter could be changed? Any idea where I might find a manual?

Right now it is just hooked to a 600v 3phase doall vertical bandsaw but given that it shows 400v at the transformer output and 175v at the transformer input I don’t want to try turning on the saw. could the vfd be interacting with the transformer in a way that I don’t understand? I understand just the basics of electricity. Start talking about power factors and back emf and my eyes glaze over.

any advice appreciated
 
You cannot measure the VFD output voltage with a conventional multimeter/RMS, the wave is a function of many smaller voltage on/off pulses that occur well beyond the capacity/frequency of typical sinusoidal AC wave. You need a scope to measure the output. You can set the display on some VFDs to show all the different operating and performance characteristics of a VFD, not so on the cheaper Chinese ones, let alone programming limitations. There are tons of HY manuals on the net. "HY VFD manual"
www.fluke.com

How to Measure Output Voltage from a VFD to a Motor

How to measure output voltage from a VFD to a motor
www.fluke.com www.fluke.com

You cannot use the VFD output to drive a power transformer if that is what you are doing. So maybe add some clarity as to how you have it hooked up, specifications of what your driving, and what are the issues or problems your are having.
 
The most obvious response might be to go back to the vendor to get the English version of the manual? Can't answer the other questions, although driving a transformer seems unlikely.
 
So a fluke set to
mksj said:
You cannot measure the VFD output voltage with a conventional multimeter/RMS, the wave is a function of many smaller voltage on/off pulses that occur well beyond the capacity/frequency of typical sinusoidal AC wave. You need a scope to measure the output. You can set the display on some VFDs to show all the different operating and performance characteristics of a VFD, not so on the cheaper Chinese ones, let alone programming limitations. There are tons of HY manuals on the net. "HY VFD manual"
www.fluke.com

How to Measure Output Voltage from a VFD to a Motor

How to measure output voltage from a VFD to a motor
www.fluke.com www.fluke.com

You cannot use the VFD output to drive a power transformer if that is what you are doing. So maybe add some clarity as to how you have it hooked up, specifications of what your driving, and what are the issues or problems your are having.
Click to expand...

ok thatwould explain the blinding flash! I ”was” running a 220v vfd to generate 3phase power and ran that into a 3phase transformer to step up to 600v. So I guess the transformer messes with the vfd somehow? Can you explain? Anyway, after readingup a bit and learning that the meter was probably reading incorrectly and everything else seemed to be working I tried to turn on the saw. That’s when the flash happened. Ittripped the 25amp breaker and fried the vfd and made a loud pow.

so I guess I need to use a rotary converter?
 
WHY would a transformer not work????
The arrangement of coils in a transformer are VERY similar to those in a motor - for which a VFD is designed - except that no torque vector is generated. The fact that the output wave form isn't quite sinusoidal would have EXACTLY the same effect on a transformer as it has on a motor.....
I would be interested for you to find the root cause of the "flash".
You didn't by chance have the VFD already running when you switched on the bandsaw, did you???? You must NEVER switch a load downstream of a VFD - either on or off (adding or subtracting a small load like a coolant pump has been successful for lots of people).
 
Last edited:
Joe in Oz said:
WHY would a transformer not work????
The arrangement of coils in a transformer are VERY similar to those in a motor - for which a VFD is designed - except that no torque vector is generated. The fact that the output wave form isn't quite sinusoidal would have EXACTLY the same effect on a transformer as it has on a motor.....
I would be interested for you to find the root cause of the "flash".
You didn't by chance have the VFD already running when you switched on the bandsaw, did you???? You must NEVER switch a load downstream of a VFD - either on or off (adding or subtracting a small load like a coolant pump has been successful for lots of people).
Click to expand...

i had to have the vfd running as it powers the motor contactor on the band saw
 
VFDs and transformers on the output do not play well together. You would be better off getting a 1P 220 to 440V transformer and then using a 440 1P to 440 3P VFD to drive the motor. This way you will still be using all of the features of the VFD. (assuming the motor can handle it).
Depending on just what transformer you have, certain 3P transformers can be hooked up to 1p power so there is a slight chance that the transformer you have can be used on the input side but it will be very de rated.

Another option is to use a rotary phase converter to convert the 220 1p into 220 3P and then feed that into your transformer. Not ideal but better than the VFD.

CAUTION: Semi technical stuff sort of translated into layman's terms to follow........... Read at your own risk......
Not all motors will last long on a VFD, That is why they now make most modern motors with a "Inverter Duty" rating. Technically a VFD is outputting DC. The way it works is by pulsing the DC power on and off very fast. When it is simulating the peak of the wave form the DC power is on for a longer time, as the simulated sine wave gets closer to the zero volt part of the cycle the DC power is on for a very short time. So the average of all that kind of follows the intended sine wave. But any time it is in the on part of the cycle it is outputting 312V DC.The motor insulation on the winding has to be able to handle this voltage without breaking down over time. The output of the 440 VFD will be pulsing 624V DC pulses into your 440 motor. If it is a very old motor it may not like this if you run heavy loads and make the motor work hard.

As for why the transformer will not work, I have never seen a transformer rated for inverter duty, A transformer works by having a nice clean pure sine wave power coming into it. A VFD is about as unclean of a power source as you can get, this unclean power will cause the transformer to get very hot due to the eddy currents that will be happening with all of the DC voltage spikes. I motor does not care if the input power is clean or not. They both use the some kind of power but they use it in very different ways.
 
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