The Warning

Do not assume that anything you read here is fact. Do your own research and make an informed decision. With that, I have been inundated with questions reguarding running your 50Hz MCH-5 on 60Hz current. This is a huge subject and it is important that you understand single/3 phase electricity and electrical frequency. Making a guess can result in a premature motor or compressor failure.

My Conclusion

After some research here is my conclusion. Your compressor will run on 60Hz, however the motor will spin about 1/5th or 20% faster than the number plate RPM. This in turn will spin the compressor faster than what it was designed for. I do not have the expertise to determine the effects on the MCH-5, however motor burnout and bearing failure come to mind. If your motor has starter windings, that is an addition headache to deal with.

Getting up to speed

I suggest getting up to speed by doing a BING search on "running 50hz motor on 60hz". This will get you a host of web pages on the topic. One site I like in peticular is Electric motors, generators & controls engineering FAQ . Here you will get useful information explained in both simple and technical terms. Once you understand the issues involved, making a decision will be easier.

What did I do

My compressor came with a 3 phase 50 Hz motor. The only sane way to deal with the issue was to use a single to 3 phase frequency drive inverter. The unit I used is a REGAL-BELOIT SpinMaster Plus, Model T330 . It is rated at 10Hp which is a bit of overkill for the MCH-5, however if I go to a bigger compressor in the furure I am covered. You can view the installation and programming guide for more information. Using a frequency drive inverter allowed me to eliminate the power panel that came with the compressor. I was able to duplicate all the panel functions from the drive.

I just can not say enough good things about this drive. It took a bad situation and made it simple and easy. The unit is completely programable from a keypad on the face of the unit. It also has a terminal strip to allow peripheral switches and other control items to be connected. Here are some of the features I used in setting up my drive.

1. Wire a momentary contact switch to start the compressor.
2. Wire momentary contact switch to stop the compressor.
3. Wire a panic switch to stop the compressor.
4. Wire the compressors existing pressure shutoff switch to stop the compressor.

Here are some programable features I programmed through the keypad.

1. Single to 3 phase conversion.
2. 50HZ max output frequency.
3. On start, ramp the compressor motor up from 0Hz to 50Hz in 10 seconds. This creates a smooth and even power up with less stress on the motor.
4. On stop, ramp down using the drives dynamic brake to stop the compressor in 4 seconds.

Other possible fixes

1. Replace the motor pulley with a smaller one. Reducing the motor pulley size will reduce the spin rate of the compressor. This is a cheap and easy way to get the job done.
2. Your motor could be a 50/60Hz motor.

There are many manufacturers of Variable-Frequency Drive Inverters. You can find new and used ones on Ebay all the time. if you find one on line, download it's install and programming guide to make sure it has the features you need. All Frequency Drive Inverters are not created equal.