MA-041
–
DGA 900 Plus - Installation & Commissioning Manual - Rev 1.1
4-Mar-22
Page 27 of 99
The OLTC Monitor requires the wiring of two temperature sensors, a tap position tracker
and a Motor Torque Converter. If the Thermal Models is also installed, the Top Oil
Temperature is already available and the Top Oil Temperature sensor for the OLTC
Monitor must not be installed.
The OLTC Temperature sensor must be installed on a surface whose other side is in
contact with the OLTC oil.
The tap position input can be provided either from a resistor wheel (10
Ω
per tap change)
or from a 4-20 mA current loop. The OLTC Monitor wiring is shown in Figure 8-1.
8.1.2.1
Wiring (three phase)
The OLTC motor torque requires the installation of an active power measuring converter
(AD-LU 410, herein referred to as the Power Converter) to provide the monitor with a 4-
20 mA input. See Section 8.2 for more details.
The transformer must be de-energised and grounded before starting the
installation of the OLTC Monitor.
It is recommended that the Motor Torque Converter is installed in the OLTC motor
cabinet housing as per the wiring shown in Figure 8-5. The Motor Torque Converter
requires a power supply of 20-253 V DC or 30-253 V AC (50-60Hz).
The 4-20 mA output must be connected to the product as shown in Figure 8-1. It is
recommended to use a shielded pair 22 AWG.
Once the Motor Torque Converter has been installed and connected to the product, both
the Motor Torque converter and the product must be switched on to validate and
commission the input signals from the OLTC Position and OLTC Motor Torque Converter
(whilst the transformer remains de-energised).
