The gains should be set–up so that a critically damped response is achieved for a step change in setpoint. An underdamped or oscillatory system can be thought of as having too much gain, and an overdamped system has too little.

To set up the P gain, set the I gain to zero. Apply a step change in setpoint that is typical for the System, and observe the response. Increase the gain and repeat the test until the system becomes oscillatory. At this point, reduce the P gain until the oscillations disappear. This is the maximum value of P gain achievable.

If a steady state error is present, i.e. the feedback never reaches the setpoint value, the I gain needs to be increased. As before, increase the I gain and apply the step change. Monitor the output. If the output becomes oscillatory, reduce the P gain slightly. This should reduce the steady state error. Increasing the I gain further may reduce the time to achieve zero steady state error.

These values of P and I can now be adjusted to provide the exact response required for this step change.

Product Related Parameter Values

Frequency Dependent Parameters

 

50Hz default

60Hz default

MAX SPEED

50

60

BASE FREQUENCY

50

60

Power Dependent Parameters

 

 

Inverter Size

Factory

 

 

 

 

Setting

 

 

 

 

 

MOTOR

Size 1 : 0.25kw 230V

1.5A

 

CURRENT

Size 1 : 0.37kw 230V

2.2A

 

 

Size 1 : 0.55kw 230V

3.0A

 

 

Size 1 : 0.75kw 230V

4.0A

 

 

 

 

 

 

Size 2 : 1.1kw 230V

5.5A

 

 

Size 2 : 1.5kw 230V

7.0A

 

 

Size 2 : 1.5kw 460V

1.5A

 

 

Size 2 : 2.0kw 460V

2.0A

 

 

Size 2 : 2.5kw 460V

2.5A

 

 

Size 2 : 3.5kw 460V

3.5A

 

 

Size 2 : 4.5kw 460V

4.5A

 

 

Size 2 : 5.5kw 460V

5.5A

 

 

 

 

 

 

 

Size 3

: 6.8kw 460V

6.8A

 

 

Size 3

: 9.0kw 460V

9.0A

 

 

Size 3

: 12.0kw 460V

12.0A

 

 

Size 3

: 16.0kw 460V

16.0A

MN735

Start–Up and Operation 4–13

Page 42
Image 42
Baldor MN735 manual Power Dependent Parameters Inverter Size Factory Setting, Current