Frequency question

in article bvrtnv$10bsp6$ snipped-for-privacy@ID-215926.news.uni-berlin.de, Anthony Glambedakis at snipped-for-privacy@hotmail.com wrote on 2/4/04 2:56 PM:

My guess is that torque will be reduced. Higher frequency, higher impedance, less current, lower magnetic forces.

Bill

At the higher frequency, the motor will spin faster. This will increase the load on the motor and could cause it to fail quite quickly. It depends on how well loaded it is when running at 50 Hz. Typically, the load will increas by the speed increase squared. i.e. a 20% increase in speed will lead to a 40% increase in load. At the higher frequency, if the voltage is the same, the flux in the iron will be reduced, reducing the torque capacity of the motor. If the combination is not designed for use at 60Hz, you could have a problem.

Best regards, Mark.

Another possible solution:

Inexpensive brushless DC blowers (operating at 12 VDC and other voltages) are readily available. You will need a power supply, which can be as simple as a plug-in wall wart transformer or tap off your existing circuit.

Check out Jameco, Hosfelt Electronics, Newark Electronics, All Electronics and similar companies...

Beachcomber

good thinking but it will run faster, the slip will be a slight bit higher but it likely will survive. sam

Glambedakis

Dear friends thank you for your responces. I am marine engineer and I had never thought that I would be involved in the above subject but I did. Fortunately it was a quotation for the installation of new small a/c system on an existing ship of 60Hz power supply with fan coils of 50HZ as manufactured in my country, which we wisely postponed till things clear out. We accepted the responce of Mr Mark Empson.

"At the higher frequency, the motor will spin faster. This will increase the load on the motor and could cause it to fail quite quickly. It depends on how well loaded it is when running at 50 Hz. Typically, the load will increase by the speed increase squared. i.e. a 20% increase in speed willlead to a 40% increase in load. At the higher frequency, if the voltage is the same, the flux in the iron will be reduced, reducing the torque capacity of the motor. If the combination is not designed for use at 60Hz, you could have a problem." So we decided not to propose a converter but to find fan coil units with