Ads
related to: hvac run capacitor function
Search results
Results From The WOW.Com Content Network
A typical motor start capacitor. A motor capacitor [1] [2] is an electrical capacitor that alters the current to one or more windings of a single-phase alternating-current induction motor to create a rotating magnetic field. [citation needed] There are two common types of motor capacitors, start capacitor and run capacitor (including a dual run ...
These motors are sometimes called DC motors, sometimes EC motors and occasionally DC/EC motors. DC stands for direct current and EC stands for electronically commutated.. DC motors allow the speed of the fans within a fan coil unit to be controlled by means of a 0-10 Volt input control signal to the motor/s, the transformers and speed switches associated with AC fan coils are not required.
In both induction and synchronous motors, the AC power supplied to the motor's stator creates a magnetic field that rotates in synchronism with the AC oscillations. Whereas a synchronous motor's rotor turns at the same rate as the stator field, an induction motor's rotor rotates at a somewhat slower speed than the stator field.
[19] [20] [21] A capacitor-start, capacitor-run motor has two separate capacitors, one for starting the motor, and another for running it, and has a centrifugal switch to disconnect the starting capacitor, or a back-EMF relay connected in parallel with the auxiliary winding of the motor. This motor provides high starting torque and high efficiency.
Capacitor-run induction motors have a permanently connected phase-shifting capacitor in series with a second winding. The motor is much like a two-phase induction motor. Motor-starting capacitors are typically non-polarized electrolytic types, while running capacitors are conventional paper or plastic film dielectric types.
Typical rms AC voltage curves as a function of frequency, for 4 different capacitance values of a 63 V DC film capacitor series. The rated AC voltage for film capacitors is generally calculated so that an internal temperature rise of 8 to 10 K is the allowed limit for safe operation.