Does Running A Motor At Double Hz Increase Temp

Speed, torque, ability and voltage are all important considerations when choosing a motor. In this ii-part blog, nosotros'll dive into the specifics of motor speeds. In Part 1, we'll discuss how speed differs betwixt motor types, and in Part 2, we'll wait at when to consider adding a gearbox to the application.

Ac Induction Motor Speeds

Ac motors are unique because they are built to run at specific speeds regardless of their design or manufacturer. The speed of an AC motor is dependent on the number of poles it has and the line frequency of the power supply, non on it's voltage. Mutual Air-conditioning motor units are constructed with either 2 or four poles. A magnetic field is created in the stator poles that induces resulting magnetic fields in the rotor which follow the frequency of the changing magnetic field in the stator. Two pole Air-conditioning motors operating at 60 Hz will e'er run at approximately 3600 rpm, and 4 pole AC motors will accept speeds around 1800 rpm.

Speed = 120 x frequency (Hz) / poles of the motor

Example 120 x 60 hertz / iv poles = 1,800 rpm.

Keep in mind that the speed of an AC motor will not run at these verbal numbers—and volition be slightly lower—because in that location is a sure corporeality of slip that must be present for the motor to produce torque. The rotor will ever rotate slower than the magnetic field of the stator and is playing a constant game of take hold of up. This produces the torque to get an Air conditioning motor running. The difference between the synchronous speeds of the stator (3600 and 1800 rpm) and the bodily operating speed is called skid. (For more information on sideslip, cheque out our weblog Synchronous & Induction Motors: Discovering the Divergence .)

A control tin can exist used to change the speed of a three phase Ac motor by increasing or decreasing the frequency that is sent to the motor, causing it to speed up or dull downwardly. Additionally, many Ac controls have a single phase input so this allows you lot to run 3 phase motors in facilities that don't have 3 phase ability available.

However, this power to alter the speed isn't typically the case for single stage Ac motors. These motors are plugged directly into a standard wall outlet and operate using the set up frequency bachelor. An exception to this dominion of thumb would be a ceiling fan that runs using single phase AC motor, just has three unlike speed settings.

DC Motor Speeds

Although permanent magnet DC motors are also congenital with poles, these poles don't touch on speed like with Ac motors because there are several other factors in play with DC motors. The number of wire turns in an armature, the operating voltage of the motor, and the forcefulness of the magnets all touch motor speed. If a DC motor is running on a 12 5 battery, that is the maximum voltage available to the unit and the motor will only be able to perform at a speed rated for 12 V. If the battery is low and supplying less voltage, the speed will subtract accordingly.

Now, if you connect that aforementioned 12 VDC motor into a 24 VDC power source, your speed typically doubles. Keep in mind, operating the motor at twice the speed at the aforementioned load/torque point will cause the motor to work harder, creating additional heat that could cause premature motor failure over time.

As with three phase Air conditioning and Brushless DC motors, controls can be used with DC motors. DC controls adjust speed by varying the voltage sent to the motor (this differs from AC motor controls which adjust the line frequency to the motor).

Typical no load or synchronous speeds for an AC fractional horsepower motor are 1800 or 3600 rpm, and 1000-5000 rpm for DC fractional hp motors. If an awarding calls for a slower speed and/or higher torque, then a gear motor should exist considered. To learn more than most calculation a reducer, bank check out Part ii, "Motor Speeds Explained: When to Utilize a Gearbox."