Can we use VFD for slip ring motor?

Can we use VFD for slip ring motor?

Of course there is also slip energy recovery which is used all the time for variable speed on slip-ring motors. There are two types of torque that need to be examined. As long as the VFD can supply the voltage and current required to produce the torque, there’s no difference between a VFD and a “line” source.

How many slip rings does a wound rotor of a three-phase motor have?

The wound rotor induction motor is one of the three major types of three-phase motors. It is often called the slip ring motor because of the three slip rings on the rotor shaft. The stator winding of a wound rotor motor is identical to the squirrel cage motor.

Where is the wound rotor The slip ring induction motor used?

Slip ring induction motor is one of the types of 3-phase induction motor and is a wound rotor motor type. Because of various advantages like low initial current, high starting torque, and improved power factor, it is used in applications that require high torque, cranes, and elevators.

Why rotor speed is always less than synchronous speed?

Actual speed of the induction motor will be less than the synchronous speed. The reason for this is if the armature turns exactly at synchronous speed, then the magnetic field of the stator windings no longer cuts the rotor windings. Under this condition, no current would be induced to the rotor windings.

Can a wound rotor motor be used with a VFD?

Wound rotor motors typically are high torque-high slip motors. They have starting torque ratings about double standard motors and VFDs typically limit the starting current and torque. Older motors may not stand up to the high voltage spikes generated by the switching devices in the VFD.

Can a VFD drive a slip ring motor?

A slip ring motor is normally not designed for the extreme high du/dt values stressing the winding insulation at VFD drive (fast switching). There is a high risk that partial discharge will break down the winding isolation material causing flash-over if it is not designed for VFD.

How are slip rings connected to wound rotors?

The slip ring brushes, made of graphite, are connected to a resistive device, such as a rheostat. As the slip rings turn with the rotor, the brushes maintain constant contact with the rings and transfer the resistance to the rotor windings. Slip rings on a wound rotor AC motor.

What kind of applications can wound rotor motor be used for?

The slip ring or wound rotor induction motor (WRIM) has been used in a variety of applications. Many of these applications use the WRIM’s high starting torque capabil­ity while limiting current to start and run very high inertia loads such as hammer mills, rolling mills, centri­fuges, and rotary kilns.