no , 110v = 115v = 120v = 125v for practical purposes

What brand/model garage opener?
How are you converting 240v 50hz to run it at 110v 60hz?

It's a Chamberlain residential door opener. The model is HD400DM.

I'm using a step down transformer to convert the voltage from the 230V 50Hz to the 110V 60Hz supply. This is a common practice here and that is how we are able to use equipment designed for the US market.

Your transformer changes the voltage but not the frequency.

I'm not an expert, but unless the AC motor was designed to operate at BOTH 50 or 60 cycles per second, using something built for one, in the other, will often either work poorly or damage the motor. The cycle mismatch causes it to turn either too fast (50 motor connected to 60) or too slow (60 motor connected to 50). Devices without motors (like the dual voltage power supplies for laptops) don't have the issue, because the power supplied to the device is DC, not AC.

Whether your door opener will function adequately, or will last, is something I can't answer. Find an electrician to talk to, they may have more to add.

Also, you probably know, transformers consume a lot of electricity. You can tell from how warm they get.

Given that the duty cycle is so light and the door should be a fairly balanced load during operation, it all sounds good.

Has the system ever worked?

The opener should work OK at 50Hz. It will be slower. Call Chamberlain 1-800-528-5880 for more information.

"I'm not an expert, but unless the AC motor was designed to operate at BOTH 50 or 60 cycles per second, using something built for one, in the other, will often either work poorly or damage the motor. "

depend son what kind of motor.

An induction motor designed for 60 Hz will not operate on 50 Hz without overheating enough to fail in short order.

You CAN run a 50 Hz induction motor on 60 Hz, as long as the extra speed is not going to cause a problem with the item the motor is driving.

Klaus, are you certain the stepdown unit actually changes the frequency? I would think it would be possible to get such a unit, although the circuitry to change the frequency would make it more complicated than just a voltage stepdown transformer.

"I would think it would be possible to get such a unit"

They are usually called a motor generator pair, and take some speed changing with pulleys.

There appear to be solid state units now that convert both voltage and frequency, without moving parts.

"There appear to be solid state units now that convert both voltage and frequency, without moving parts."

Make sure you check on the 'quality' of the voltage and current waveforms under varying load.