This instrument is used to indicate the tap position of on-load tap changers employed in power transformers the on load tap changer changes the output voltage of transformer, for maintaining reasonably constant voltage by selecting proper tapping in the transformer winding. The tap position is indicated in numbers depending upon the numbers of steps used in the tap changer.
The tap position transmitter [tpt] converts the resistance input from resistance array unit of on-load tap changer in to dc current signal outputs depending upon the number of positions. The signal is connected to remote tap position indicator to indicate the corresponding tap number.
Specifications:
Signal input: suitable for 3 wire connection from resistance array
Signal output [output-1]: 4-20ma, 0-5ma, 0-20ma [to be specified]
Signal output [output-2]: 4-20ma, 0-5ma, 0-20ma [to be specified]
Burden on loop resistance: 600 ohms maximum
Resistance per step: 100, 1000 ohms [to be specified]
Number of positions: 1 - 17 [other positions on request]
Auxiliary supply: 90 - 260v ac/dc
Degree of protection of enclosure: ip40.
H.V. Test: signal terminals to body earth, 500 v ac 50 hz for 1 minute.
Power terminals to body earth, 2 kv ac 50 hz for 1 minute.
I. R. Test: 20 meg. Ohms when checked by 500 v dc megger.
