What is this used for?

[Paul.M]

Came across this the other day (not what I was working on btw) and I don't know what its used for. I'm thinking its used to monitor phase sequence or something to do with sensitive equipment probably lighting.

 

[Rockingit]

On the basis that they are just torroidal coils, it depends on what they are plugged into. Most likely is some sort of loading sensor (I/ph) for load balancing. If there's another one on the neutral as well then it could be for RCM (Residual Current Monitoring). Others here may know more.

 

[Paul.M]

Thanks rockingit, it could be for load balance but I didn't see a coil for the neutral think it may have been in one of the many enclosures. As I said its not what I was working on or near and I didn't have much time to investigate it more or take many pics, just got me curious to what its function is and thought I'd ask so I can learn.

 

[Guest123]

Are they not C.T's???

Where do the coloured cores from the coils go to???

 

[Paul.M]

Are they not C.T's???

Where do the coloured cores from the coils go to???

Into trunking so I couldn't trace them to anything without spending a bit of time that I didn't have (just powered down a section of a public building so we could connect up and test).

 

[Guest123]

The fact that they are on the tails right next to the service head suggests they are indeed C.T's and the smaller cores attached to them would connect to the electricity meter.

 

[PB1]

The fact that they are on the tails right next to the service head suggests they are indeed C.T's and the smaller cores attached to them would connect to the electricity meter.

Lenny could you please explain what CTs are? Thanks.

 

[Paul.M]

Thanks Lenny my curiosity has been satisfied.

Am I correct in saying that it works on the same principle as a clamp meter monitoring emf?

 

[Paul.M]

From Wikipedia:-

In electrical engineering, a current transformer (CT) is used for measurement of electric currents. Current transformers, together with voltage transformers (VT) (potential transformers (PT)), are known as instrument transformers. When current in a circuit is too high to directly apply to measuring instruments, a current transformer produces a reduced current accurately proportional to the current in the circuit, which can be conveniently connected to measuring and recording instruments. A current transformer also isolates the measuring instruments from what may be very high voltage in the monitored circuit. Current transformers are commonly used in metering and protective relays in the electrical power industry.

 

[Guest123]

Lenny could you please explain what CTs are? Thanks.

C.T's are Current Transformers and are used to drive the electricity meter on all 3 phase supplies above 100A as this is normally the point at which the current becomes too high to connect directly into the meter.

 

[UKMeterman]

The most important thing to remember with CTs is to NEVER EVER open circuit the secondary when the primary is connected to a supply, If they are operated into an open circuit then a very high voltage is generated...

 

[Knobhead]

The most important thing to remember with CTs is to NEVER EVER open circuit the secondary when the primary is connected to a supply, If they are operated into an open circuit then a very high voltage is generated...

I’m glad someone pointed that out. The dangers of CT’s are very misunderstood.

 

[Marvo]

CT's are often used for metering but also for monitoring for other applications. They could be there for other data acquisition/recording systems or even as part of a load shedding system.

 

[PB1]

Thanks chaps. Every day is a school day - for me at least.

 

[mogga]

Probably used for a digital meter that can be monitered remotely we had to fit them in Tesco,Morrisons for bakery chicken ovens so that some bean counter in head office could have more numbers to put on a spreadsheet somewhere and change times for baking ect by produce sold and stock levels Some had to be full shut downs to get the CTs on one of the guys forgot when taking a temp one off he disconnected the coil split the case and got a nice wee BIFFFFFF very simple mistake to make but could have been deadly