This trip indicates a DC bus component over temperature based on a firmware thermal model. The drive includes a thermal protection system to protect the DC bus

components within the drive. This includes the effects of the output current and DC bus ripple. The estimated temperature is displayed as a percentage of the trip

level in Percentage Of d.c. Link Thermal Trip Level (07.035). If this parameter reaches 100% then an OHt dc bus trip with sub-trip 200 is initiated. The drive will

attempt to stop the motor before tripping. If the motor does not stop in 10 seconds then the drive trips immediately.

Source

Control

system

It is also possible in a multi-power module system for d.c. link over-temperature to be detected from within the power stage. From this source the estimated

temperature as a percentage of trip is not available and the trip is indicated as follows:

Source

Control

system

Recommended actions:

Check the AC supply voltage balance and levels.

Check the DC bus ripple level.

Reduce duty cycle.

Reduce motor load.

Check output current stability. If unstable;

Check the motor map settings with motor nameplate (Rated Frequency (05.006), Rated Current (05.007), Rated Speed (05.008), Rated Voltage

(05.009), Rated Power Factor (05.010) and Number Of Motor Poles (05.011)) - (All modes).

Disable slip compensation (Enable Slip Compensation (05.027) = Off (0)) - (Open-loop).

Disable dynamic V to F operation (Dynamic V To F Select (05.013) = Off (0)) - (Open-loop).

Select fixed boost (Open-loop Control Mode (05.014) = Fixed (2)) - (Open-loop).

Select high stability space vector modulation (High Stability Space Vector Modulation (05.019) = On (1)) - (Open-loop).

Disconnect the load and complete a rotating auto-tune (Auto-tune (05.012) = 2) - (RFC-A and RFC-S).

Auto-tune the rated speed value (Rated Speed Optimisation Select (05.016) = 1) - (RFC-A and RFC-S).

Reduce speed loop gains (Speed Controller Proportional Gain Kp1 (03.010), Speed Controller Integral Gain Ki1 (03.011) and

Speed Controller Differential Feedback Gain Kd1 (03.012)) - (RFC-A and RFC-S).

Add a speed feedback filter value (P1 Feedback Filter (03.042)) - (RFC-A and RFC-S).

Add a current demand filter (Current Reference Filter 1 Time Constant (04.012)) - (RFC-A and RFC-S).

Check encoder signals for noise with an oscilloscope - (RFC-A and RFC-S).

Check encoder mechanical coupling - (RFC-A and RFC-S).

Trip

OHt Inverter

Value

Short description

This trip indicates that an IGBT junction over-temperature has been detected based on a firmware thermal model. The sub-trip indicates which model has initiated

the trip in the form xxyzz as given below.

Source

Control

system

Control

system

Recommended actions with sub-trip 100:

Reduce the selected drive switching frequency.

Ensure Auto-switching Frequency Change (05.035) is set to Off.

Reduce duty cycle.

Decrease acceleration / deceleration rates.

Reduce motor load.