# Power factor of motor with VSD?

• Martinz
In summary, if a motor with a full load power factor of 0.8 and starting power factor of 0.3 is operated with a VSD set at a power factor of 0.95, the power factor during starting will be 0.3. At full load, the motor power factor will remain at 0.8 while the VSD will need to be rated to handle the reactive VAR of the motor load. A PF correction circuit can be used to maintain a power factor of 0.95 for the VSD.
Martinz
TL;DR Summary
Power factor at the motor with VSD
If I have a motor with a full load power factor of 0.8 and starting power factor of 0.3 and I install a VSD to run it with a datasheet power factor of 0.95, will the power factor during starting be 0.3 or 0.95? And at full load?

Cheers!

Welcome to PF.

The power input to the VSD should be maintained at 0.95 by a PF correction circuit that controls the switching input rectifier.

The DC reservoir capacitors isolate the PF of the motor load, from the PF of the main supply.

The motor PF will not change, but the VSD must be rated to handle the reactive VAR of the motor load.

Delta Prime, Averagesupernova and russ_watters

## What is power factor and why is it important for motors with VSD?

Power factor is a measure of how efficiently a motor uses electrical power. It is important for motors with VSD because a low power factor can result in higher energy costs and reduced motor performance.

## How does a VSD affect the power factor of a motor?

A VSD, or variable speed drive, can improve the power factor of a motor by adjusting the frequency and voltage of the electrical supply to match the motor's load. This results in a more efficient use of power and a higher power factor.

## What is the typical power factor range for motors with VSD?

The power factor range for motors with VSD can vary depending on the specific motor and VSD system. However, a typical power factor range for these motors is between 0.95 and 0.99, with a higher power factor being more desirable.

## How can a low power factor be corrected in a motor with VSD?

A low power factor in a motor with VSD can be corrected by adding power factor correction equipment, such as capacitors, to the motor's electrical system. This helps to improve the power factor and reduce energy costs.

## What are the benefits of maintaining a high power factor in motors with VSD?

Maintaining a high power factor in motors with VSD can result in lower energy costs, improved motor performance, and reduced wear and tear on the motor. It can also help to avoid penalties from utility companies for low power factor usage.

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