D01 Current Lim; D02 I2T - Zener MSC-3 Instruction Manual

MSC-3 Start Up

D01 CURRENT LIM

Range: 22...125% of the MSC-3 current rating (model dependant)
• Press  to edit the value.
• Press ▲/ ▼ to make changes to the value.
• Press  to accept the new value OR
• Press ESC to abandon the value change.
This sets the maximum output current of the MSC-3. If excessive load is applied to the motor, the drive
will only apply this amount of current to the motor until the overload condition is removed. Current
limiting is achieved by reducing the speed of the motor. The Current Limit value cannot be set higher
than the maximum output current for the drive.

D02 I2t

The I2t feature estimates the heating of the motor according to the motor load. When the estimated
heating exceeds I2t setting, the drive will trip on I2t. For a motor running at 110% of its I2t current this
will take approximately two minutes. The time to trip will shorten the further the motor current exceeds
the I2t value.
If power is removed from the drive after an I2t trip, the motor should be allowed to cool down before the
inverter is restarted. Motors running highly loaded at low speeds should have external cooling and an
external motor thermal sensing device such as microtherms or thermistors for protection.
The I2t feature has the ability to set the trip threshold as a function of output frequency. This allows the
I2t to protect motors that have reduced cooling at low speeds because they are not externally cooled.
The diagram below is an example of the I2t trip threshold profile.
I2t
D020 I2t (Trip level)
D021 I2t zero Hz
78
D01 CURRENT LIM
40.0 Amps
D022 I2t CNR Hz
I2t Speed Pro le
IM00120 IM00120
Hz