Monthly Archives: July 2017

Synchronous Motor Operation

Let a three-phase voltage be connected to the stator of a synchronous electric motor, in a second in which the currents in each coil, with the current in the coil a-a ‘in position 1.

Due to the poles created by the field (2-pole motor), one conductor is located on the N pole and another on the S pole. From the relationship between the current in the conductors and the fields, as the conductor is effective, the upper polar face is exposed to A torque to the right, while the lower pole face is subjected to a torque to the left.


Therefore, the rotor is subject to a torque that would tend to reallocate it clockwise. For the current in position 2 is the alternating current and the rotor is exposed to a torque that would tend to move it in the counterclockwise direction.

Due to the inertia of the rotor, the torque formed in one second is zero because the rotor was precisely drawn alternately in the clockwise and counterclockwise directions 60 times at that time for the frequency of 60 Hz. If the rotor is driven at the speed Synchronous, in the second in which the direction of the current is reversed, the field is changed, which will allow a liquid torque.

Balancing and Coupling

Equipment that for different reasons may be unbalanced may cause vibrations, which may lead to possible engine damage. It is recommended that the motors in general be balanced dynamically with a half-key in a vacuum, that is, uncoupled. If the buyer wants a specific balance, it must be manifested at the time of purchase.

Transmission elements such as couplings and pulleys, among others, need to be balanced before they are inserted into the axles of the engines. The level of engine balancing quality must follow the specifications and standards in force for each product line respectively. It is recommended that maximum balancing deviations be entered in the installation report.


The couplings are used to transmit torque from the motor to the driven machine in question. When using a coupling, it is necessary to use appropriate tools for assembly and disassembly, avoiding damage to the motor and flexible couplings, which may absorb minor misalignments during the operation of the equipment. The loads that are within the speed limits reported by the coupling and engine manufacturer should never be exceeded.