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Synchronous Motor Overview

What is a Synchronous Motor

Synchronous motors are naturally constant-speed motors. They operate in synchronism with line frequency and are commonly used where precise constant speed is required. The synchronous motor is an electric motor that is driven by AC power consisting of two basic components: a stator and rotor. Typically, a capacitor connected to one of the motor's coil, is necessary for rotation in the appropriate direction. (No capacitor is required for our UDS model that employs a single coil with an internal ratchet to determine direction). The outside stationary stator contains copper wound coils that are supplied with an AC current to produce a rotating magnetic field. The magnetized rotor is attached to the output shaft and creates torque due to the stator's rotating field. The motor's synchronous speed is determined by the number of pair poles and is a ratio of the input (line) frequency. Similar to our stepper motor, our synchronous motor can provide motion solutions for both rotational and linear applications.

Synchronous Motor Basics

The Permanent Magnet (PM) synchronous motor is highly efficient and can be stalled when voltage is applied without damage to the motor winding. These motors are characterized by their synchronous speed, power consumption, pole pairs, starting and running torque.

  • Synchronous speed is defined when the rotor under load reaches a constant speed and is determined by the number of motor pole pairs and input frequency.
  • Power consumption expressed in Watts is the amount of energy the motor requires under no load conditions.
  • The rotor pole pairs are the number of north and south segments the rotor contains.
  • Starting torque is the load the motor is capable of moving from a standstill.
  • Running torque is the amount of torque that the motor is capable of producing without falling out of synchronism.

Our rotational synchronous motor can be combined with our full line of Gearboxes to increase torque and reduce speed.