It should be pointed out that the resultant speed is dependent on the load placed on the motor.What is actually being done is the weakening of the motor by reducing the voltage across the winding (the resistor acts as a voltage divider).The did not make it past 120 Hz before the rotor literally exploded!
As stated above, for decades the three phase motor was designed for a specific rpm based on the frequency of the incoming line.From the time the three phase induction motor was invented (circa 1889) it was a foregone conclusion that it would run at a speed dictated by the frequency of the power supply. kostenlose kontakte Bielefeld If a different speed was needed a device was attached to the output shaft of the motor to accomplish the task.Only rarely were devices employed to change the frequency of the incoming power; many of these rotary frequency changers are still in use however.With the growing popularity of VFD electronic drives a whole new industry was opened.
State different applications of capacitor start single phase induction motor
Like many other things, just because you change the speed of a winding design doesn’t mean you should do so.Before considering a change like this, consult a motor expert, like the experts at Gem State Electric, for example.(Now tell the truth – you were expecting that commercial weren’t you? ) If you do not have access to three phase power but need to change the speed of your motor you are still in the game. He needed more water to irrigate his field but the utility would only allow single phase power to be brought to his meter location.The “lost” voltage is converted into heat which, for all practical purposes, is wasted into the atmosphere.
Most large single phase motors can’t (or, more correctly, shouldn’t) be operated at reduced speeds.Companies now marketed the devices as a great way to save energy, particularly in variable torque applications such as pumps and fans. input to create an easily variable frequency output the speed of the motor is now adjustable.By changing voltage frequency with a constant ratio the output torque is consistent from nearly zero to full line voltage.It was then possible to operate a motor at virtually any speed from 0 to nameplate rpm with the twist of a dial. Like anything else, each method has its up side and down side.Next came the ability to operate name plate rpm, follow an electrical signal for “automatic” speed adjustment to maintain system settings, and set up PID loops. Some (not all) small single phase motors can be operated at various speeds through the addition of a resistor(s).