6
RMO30T Designated Use, Functionality
4.2 Tap Changer Test
The TapC menu offers a user friendly way of measuring winding resistance in tap changers.
RMO30T test set measures the winding resistance of individual taps of a power transformer’s tap
changer, and checks whether the On-Load Tap Changer (OLTC) switches without a discontinuity. In the
moment the tap is changed from tap to tap, the device detects the sudden, very short drop of the current
flow. A properly working tap changer differs from a malfunctioning one in a discontinuity during the
change, by the magnitude of the current ripple value. An interruption will result in a much higher ripple
value than a properly functioning tap changer.
Note:
In
TapC
menu only Ch:1 is the active channel. Maximum test current selected in the
TapC
mode is
10A.
At the start of the test a check of cable continuity is performed. In case of disconnection, an alarm is
activated, and the error message is shown on the display.
Note:
Using RMOWin-T5 in
TapC
menu the results could be stored to a PC. By pushing the
Ω
buton a
resistance result and current ripple value are stored in internal memory location, and the memory
location is automatically increased by one.
