What does this signal name indicate in MK V - L51BT1 & L51BT2?

In IO_ASG file they mentioned it as "turbine compartment ventilation fan 1&2 indication", but v has L52BT1&L52BT2 as their running indication, could anyone tell me?

 

Hello,
FYI, 51 - stands for AC Time over current relay.

Relay that functions when AC inputs current exceeeds predetermined value and in which input current and operating time are inversely related through a substantial portion of the performance range. Common Application is for - System phase/ground fault relay

Please check drawings of breaker and how r they wired.

Best Regards,
Mambo

 

I think there's some kind of typographical error. Stranger things have been known to happen, but putting a time over-current relay on a compartment ventilation fan seems to be kind of over-kill.

Generally, and we can't know for sure because we can't review the configuration for the site (only the people on site can do that), a lot of AC motor starters are equipped with a status indication to let the control system know if the starter is energized or not, and this is supposed to be a good indication of whether or not the fan or the pump the starter is driving is running.

In the case of turbine compartment vent fans, I've seen motor starter status contacts called L52BT1 for the first vent fan's motor starter and L52BT2 for the second vent fan's motor starter.

I think the originator mis-typed the signal names, but only the originator knows for sure.

But, the originator should be able to trace the wiring from the inputs to the devices and ultimately determine if they're coming from motor starter status contacts or time over-current relays.

It could even be a typo in the software (yes; that did happen on more than one occasion), though it's not likely.

If the inputs were really connected to time over-current relays, one would think they would also drive alarm(s) to indicate the relays had actuated. That may be another clue. Motor starter status contacts were usually used in sequencing to start the lag device should the lead device not be running, or even just to drive indications on displays.

It will be (more likely, would be) interesting to see if the two dis-similar device numbers were typographical errors. It would also be interesting to know how the inputs were described in the I/O Report (TC2KREPT.TXT).

 

Hi,

In Mark V this signal name indicates:

L51BT1 - the breaker for the 88BT1 motor of fan1 On turbine compartment ventilation. The reason of the alarm L51BT1_ALM is a problem on the breaker of 88BT1 of the fan 1; 88 BT1 motor overheating or electric protection.

L51BT2 - turbine compartment ventilation fan 2, same explication as above.

If you see the American National Standards Institute you will find this:
49 : MACHINE or TRANSFORMER THERMAL RELAY
50 : INSTANTANEOUS OVERCURRENT or RATE of RISE RELAY
51 : AC TIME OVERCURRENT RELAY
52 : AC CIRCUIT BREAKER or CONTACTOR

I can send you the PDF file of ANSI.