Running 120V/60 hz Single Phase Motor on 230/50 hz
Running 120V/60 hz Single Phase Motor on 230/50 hz
(OP)
I have 3 ventilators that are rated for 120V/60 hz however my supply is 230/50 hz. I can use a step down transformer 230/120V however because of the frequency change i won't be able to have the same rpm. I was thinking to use a step down transformer and a vfd to overcome this but could not find any products that does both.





RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
A VFD can be programmed to put out any voltage BELOW the incoming line voltage. So you would feed the VFD with 230V 50Hz and program it to put out 120V at 60Hz as the top speed. But be careful, a 120V packaged unit like that is going to expect to get a hot and a neutral, and sometimes they bond the neutral inside of the unit (they are not supposed to but it happens). That would be very bad for the output of a VFD.
I'll warn you though, this is likely FAR more expensive than just buying a new ventilator motor that will run correctly at 230V 50Hz.
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RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
Some types of single phase motor can run on a 'dumb' scalar drive but we are getting into specific types of motor and types of drive to do this. For the cost of a ventilator is it really worth it?
RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
if their switch is a 50/60 design. If not, then you will need a 50HZ motor.
RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
Buying a 50hz motor won't do you any better than using the one you have. Transform the voltage down to keep the V/Hz ratio the same and the motor you have will run the same rpm as new 50HZ motor.
If the ventilator fan is mounted on the motor shaft you will either have to find a VFD that will work with your motor or get another fan. Unless it has pulleys and a belt.
At 120V, it can't be much of a ventilator. How about just buying a new one rated for 230V, 50HZ and the CFM you need.
ice
RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
You're correct up to a point, but you're overlooking some other effects of the change in frequency: at 5/6 of the original speed the fan won't require as much power and won't move as much air, and won't develop as much pressure if in a ducted application. Overall it's performance will be significantly reduced. If the OP selected the fan based on a requirement for a certain airflow then the fan which had adequate performance running on a 60Hz supply probably won't be adequate running on a 50Hz supply.
RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
As I recall:
ice
RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
ahmetkazici mentioned the rpm change so I figured he knew there would be a change in the cfm ~5/6, pressure ~25/36, and a change in the power ~125/216. He did not appear to need a basic physics lesson.
My post was aimed at: Why engineer a $500 fix when a $100 fan will fix the issue, have less parts to fail, easier to T-shoot down the road. Its only installed once - but it has to be repaired for the next 30 years.
ice
RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
Yes, you did say that. And I read what you said. Hence the reason for my post. A new 50hz ventilator motor won't fix the problem. (Well, unless you have a source for 1.7 pole motors
However, you are correct, I did not say, buy a new "ventilator". I sloppily use "new one".
ice
RE: Running 120V/60 hz Single Phase Motor on 230/50 hz
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies