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Sigmatek FDD Sizes 7 to 9 Power Installation Guide
6.7
Motor overload protection and thermal memory retention
All drives incorporate internal overload protection for the motor load that does not require the use of
an external or remote overload protection device.
The protection level is adjustable and the method of adjustment is provided in the relevant Control
User Guide. Maximum current overload is dependent on the values entered into the current limit
parameters (motoring current limit, regenerative current limit and symmetrical current limit entered as
percentage) and the motor rated current parameter (entered in amperes).
The duration of the overload is dependent on motor thermal time constant. The maximum
programmable time constant depends on the drive model.
The method of adjustment of the overload protection is provided.
The drives are provided with user terminals that can be connected to a motor thermistor to protect
the motor from high temperature, in the event of a motor cooling fan failure.
6.8
External Class 2 supply
The external power supply used to power the 24 V control circuit shall be marked: "UL Class 2". The
power supply voltage shall not exceed 24 Vdc.
Summary of Contents for 074.00660
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