Converting from American Voltage220v 60hz to Romanian 230v50hz

As immediate solution, a variable voltage transformer, called VARIAC, might help. A 5hp part is rather big and costly though.

Rene

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Another possibility would be to use an inverter to generate the 60Hz, though I am not sure of how this would compare cost wise.

Yes.

A line voltage reduction to about 176VAC 50Hz should give you most of the performance at 20% less (fewer?) RPMs.

This can be achieved by using a buck transformer arrangement, so you only need a fraction of the transformer VA size that you'd otherwise require. If you're getting 230V nominal, that's 54V, so a 230V to

55VAC/50Hz transformer good for about 20A should do it (about 1000VA). Or just swap out the motor for a local one. That's for the main motor, don't know about the other one-maybe it has some kind of DC power supply that doesn't care so much about the Hz.

Best regards, Spehro Pefhany

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Look closely at the motor nameplate.

If it is an AC-only motor (no brushes)::

If it says "50-60Hz" then it will probably run okay, just a bit warmer, on 50Hz. Note that the RPM's will go down to 5/6 of the 60Hz RPM (usually 1750 or 3500 RPM).

If it a AC-DC motor (has brushes): It may have a governor to regulate the speed. Perhaps the governor will have enough range to regulate the RPM well at 50Hz, or it may be possible to adjust the motor governor to have it run at the original RPM.

I wouldnt try running a 5HP motor without haveing a clear idea if it was going to work! A 5 HP motor can make a lot of smoke, and be expensive to replace.

The ideal solution is probably a PWM based motor speed controller. You can sometimes get them fairly cheaply on eBay or surplus. However, for 5 HP, most of them require 3 phase input so they don't need huge capacitors for the DC link. V/F drives are also very good for adjusting speed, and they have built-in overload protection and other nice features. However, they are also mostly three phase output, and I don't think they like single phase loads.

Paul

In conversations with Baldor and Leeson motors over the last 27 years: Since the ratio of 230/60=3.83 is close to the ratio of 220/50=4.0, then the motor should be generally ok, if the motor is triple rated (460/230/208). Especially with the 208 rating, that is a "stronger" built motor winding. BTW, 208/60=3.47 and 208/50=4.16. If the ratio approaches 230/50=4.6, then absolutely you should NOT use that

60 hz motor at 50 hz. In other words, 230/50is bad for that motor, 220/50 is ok. The big difference here is that we are changing (both) voltage and frequency. Been using motors around the world, and sometimes, mtr mfrs simply replate the motor to 220/50. But not, not, to 230/50 or 240/50 unless the mtr has a very special winding.

Best-- Ron

Well, it's not 5 HP, but I do have a JET bandsaw with a 1.5 HP motor that is designed for 220v, 60 Hz, and I run it quite happily on

230vac, 50 Hz. It has run for 2+ hours in one day, in stretches of probably 20-30 minutes. It gets barely hotter than ambient, but I am not pushing it too hard.

IMO, if you can keep your hand on the motor, it should be OK, at least that's my rule of thumb for my equipment.

Barry Lennox

Are you sure the motor is rated 220V 60Hz? As I understand it the US national household voltage is set by ANSI C84.1 and is supposed to be 120V

+/-5% under normal circumstances. The stuff coming out of my outlets usually measures around 117V-120V. Since we obtain our 120V supplies from center tapped transformers, the "220V" supply should actually be 240V in the United States. I would guess that since everyone including many fellow United Statesians think we run on a 110V/220V system, we must have done so in the past. I assume over time we have increased the voltage supplied slightly to improve transmission efficiency and power handling capability with negligible changes in the infrastructure.

Anyway, if your motor is old, perhaps it really was designed for 220V 60Hz, but if it is relatively recent, I would expect it to be designed for and rated at 240V 60Hz instead. If that were the case, then running it at 230V

50Hz wouldn't be as much of a stretch.