3.5.8 Motor current measuring
Unisab III can be supplied with a 0-1 Amp AC signal directly from a current transformer in the
compressor motor starter or supplied with a 4-20 mA signal from a current transmitter/VSD.
In the Configuration/Drive menu, select Motor Input Signal for a 0-1 Amp or 4-20 mA signal
source. In the same menu, select Display for Amp.
The value for the current ratio of the current transformer or transmitter must be entered in
the value Configuration/Drive Motor range Amp to get a correct reading of the current.
Next, select menu Control values/Motor/Current/Control and the following picture appears:
In Set point 1 enter the full load current of the motor as stated on the name plate. In Set
point 2 a lower value may be entered if current should be limited in certain periods.
Move the cursor to Set point 1, press
to enter the parameter change field, use and to
adjust the value and then press
to store the value.
You can switch between two set points by opening or closing a digital input. See wiring dia-
grams.
Open input = Set point 1. See also section 3.2. Limiting functions.
3.5.9 Motor power measuring
Unisab III can be supplied with a 4-20 mA signal from a power transmitter of 0-xxxx kW. En-
ter the power ratio of the power transmitter in the value Configuration/Drive Motor range kW
to get a correct reading of the power output. In the menu Configuration/Drive, select Display
for kW. Then select the menu Control values/Motor/Power/Control and the following picture
appears:
Compressor control and surveillance
Engineering manual - Unisab III 1.10
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