How to select variable frequency drive

1. First step

Confirm the motor voltage level and motor power.

2. Second step

Confirm the application type:
(1) Light load, keep the first step selection;
(2) Heavy load, select one or two sizes higher.

3. Third step

Check current:
Decision condition: normal running current > selected VFD rated current x 1.1?
(1) Yes, increase the power of VFD;
(2) No, keep the original selection.

4. Forth step

Check the temperature and altitude:
(1) Temperature should be -10~50 degree;
(2) Altitude should be less than 1000m, otherwise think about derating.

5. Fifth step

Stop mode confirmation:
(1) Fast stop, needs additional braking system (Braking Unit and Braking Resistor);
(2) Normal stop, no need additional braking system.

6. Sixth step

Peripheral devices:
(1) Input reactor, remover harmonics, avoid surge current etc.
(2) Output reactor, if the motor cable's length longer than 50m.
(3) DC choke, increase the power factor.
(4) Output filter, improve output current waveform.