Before starting up the motors, take care that they are connected the right way: at 400V inverters, motors usually have to be connected as ‘star’, at 200V inverters, motors usually have to be connected as ‘triangle’. Nevertheless there are some motors that work in another way, so please refer to the manual of the connected motors upon any doubt.

Connect the azimuth and elevation motors directly to the frequency inverters. Use shielded cable only. Take care, that the shield is connected to the cabinet or frequency inverter ground with low impedance and is NOT connected to the crankcase or antenna ground. Also take care that the unshielded part of the cable is as short as possible. To ensure proper ground connection in the cabinet, there are two possibilities:

  1. connect the shield to the PE terminals at each frequency inverter. Take care, that the shield cable is as short as possible.

  2. there are two brackets that can be used to ground connect the shield extensive. You have to remove the outer insulation of the cable in the area of this bracket. Take care, that shielding is not damaged during removing of isolation. Feed the cable through the bracket ad close it by considering, that the de-insulated part fits the bracket. If you decide to go with 1), you can nevertheless use this bracket as strain-relief for the cables.

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If your ACU-ODU is equipped with a polarization drive, the terminals are located at the rail where the other terminals are mounted at. Here it is not necessarily needed to use a shielded cable. If you nevertheless use a shielded one, take care, that the shield is connected to the PE terminal of the terminals and is NOT connected to the crankcase or Antenna ground! Please refer to the schematics shipped together with your sat-nms ACU2-ODU for more detailed informations and pin descriptions.

The ACU knows two different configuration modes to control a motor driver. They are called ‘DIR-START’ and ‘DUAL-START’. In ‘DIR-START’ mode, the ‘FWD’ signal switches the motor on/off, the ‘REV’ signal controls the motor direction. In ‘DUAL-START’ mode, the ‘FWD’ signal switches the motor on in forward direction, ‘REV’ activates the motor in reverse direction. This configuration mode is convenient to control a motor with relays. At sat-nms ACU2-ODU all axis have to be configured as DUAL-START.