460V 60Hz Equipments

dear,

I have seen textile factories being rewinded the similar motors, to tackle the speed problems.

But, the speed variation encounterd is only of 6%. lesser then the original speed, which they may be able to over come by VFDs in their system.

Then, there is no need of modifications at all.

Just connect the 60 Hz - 460 V motors to 380V - 50 Hz supply, factory will run..

I think that the speed reduction is 16.6666% IE: RPM at 60 Hz/6 x 5 = 50Hz Speed

Due to the lower speed the fan will not transfer as much air and would run a little bit more hotter but it should not be a problem.

Cheers

Joe

Hi J Raef, I am most impressed, I never have known that calculation for operating motors at different frequencys and voltages, I have always consulted a motor rewinder but, this I know will come in handy in the future, thanks mate you have my vote.

Thats the great thing about this forum, you get more than you put in.

Best Regards

Joe

The only reason to rewind all ac motor is basically to standardized with our mill motor spare parts. This is just to prevent further complication later on if someone take 460V motor to another place without refering at the motor nameplate

As for the AC motor using inventer, we might just maintain as it is by just adding autotransformer. Thanks to JRaef for highlighting the idea up.

But for DOL motor like trim blower and vacuum pump which are subjected to speed downgrade if connected to 50hz, we do not have much practical choice other than replacing those motors.

GA for both posts JR. Nicely covered.

Another option would be to install a 460VAC, 60Hz 3-Ph generator driven by a "local" 380 VAC, 50 Hz motor (or install a small CoGen unit with same outputs). Everything would work as before with small added operating cost (or none with proper CoGen system).

Another good suggestion. will consider that one with our project team. Thanks Energygod

One more thing that I did not see mentioned. If you are going to run the motors at 50Hz, watch that they dont overheat. The internal cooling fans in the motors will not move as much air due to the lower speed. This may or may not be a problem. Depending on how conservatively they were designed.

If the motors are supplied by inverters (vfd's) as the original post indicated, the inverter output to the motor would be 60Hz nominal anyway. As JRaef said, the inverters don't care about incoming frequency, it's immediately rectified to DC. The inverter output is already compatible with the existing motor it supplies.

check the normal load amps if it is within the name plate current it should be okay, only the motor rpm will be less.

Hello Sir..

As per your query i would like to suggest you that you have to installe a Servo Voltage Stablizer On the LT side of your Existing transformer and supply the output voltage of that stablizer to your machine. With the 380 Volts 50 Hz supply your machine will work fine.

Specification of Stabilizer.

I/P Voltage: 320-480 Volts 3-Phase, 50 Hz

O/P Voltage: 380 Volts 50 Hz.

with this requirement your machine will work fine.

i'm also working in stabilizer company and we have already supply the stablizer for that kind of requirement

For further detail feel free to contact me.

Kunal Gautam

094645-28115

Hello Sir..

As per your query i would like to suggest you that you have to installe a Servo Voltage Stablizer On the LT side of your Existing transformer and supply the output voltage of that stablizer to your machine. With the 380 Volts 50 Hz supply your machine will work fine.

Specification of Stabilizer.

I/P Voltage: 320-480 Volts 3-Phase, 50 Hz

O/P Voltage: 380 Volts 50 Hz.

with this requirement your machine will work fine.

i'm also working in stabilizer company and we have already supply the stablizer for that kind of requirement

For further detail feel free to contact me.

Kunal Gautam

094645-28115

You don't mention wether or not the motors are controlled via VFD but if so most (as JRAEF said you have to ask) will allow you to power the VFD for 380/50 and run the motor at 460/60. Since the incoming AC is converted to DC before being chopped up the in and the out don't have to be the same. However current draw will increase on the line side so that would have to be taken into consideration.

As for the controls if your machine has its on dedicated control transformer for 120V controls you should just be able to switch out the 460-120 for a 380-120 transformer.

Shawn

You cannot supply a VFD with 380V and have it put out 460V, it cannot create voltage from thin air. That's why I said they would need autotransformers in front to step the voltage from 380 to 460V.

I'll just shut up now as I'm an idiot. I've done the opposite (460 IN/380 OUT) and didn't stop to think.

Shawn

No your not an idiot, you just did what we all do sometimes. Didn't stop to think it through. I do that a lot...

I only responded because there are people who read this forum and take everything posted as gospel.

Hey we don't have to install VFD. the machine will work on 380 Volts 50 Hz very well...

Hello,

The replays on your problem also give me positive ideas in my future needs. Specially the replay of JRAEF, thanks anyway. Nonetheless, if you required the same rpm hopefully you have some space to introduce a reducer (gear box), belt pulley, etc.

erel

has anyone seen the film "Not another teenage movie" (or something like that). Well this post is another "Not another 50Hz/ 60Hz post". JRaef (who by the way is excellent in these matters) never seems to tire in answering these questions.

yes I do... but after I have ignored a few, I get interested again.

Well you get a gold star (and GA) from me.

Hook it up and try it! The inverters first rectify the incoming voltage then create the voltages based on the parameters selected. If you do not run at full power I'll be willing to bet it will work.

I have ran 3-Phase 460 servos on 1-phase 240, just not at full power.