CPT

Status
Not open for further replies.
S

sdilucca

Member
hello... i guess i am what you call a rookie engineer (just graduated, and curriculum was more geared to electronics, not power)... i have all sorts of simple questions... hopefully one of you guys can take pitty on me and provide simple answers... thanks....

What is a Control Power Transformer (CPT)? :confused:
 
Re: CPT

I did a quick search and got a lot of results. These images came from here.

acbairdisconnect%20copy.gif
controlpowertransformer.gif
 
Re: CPT

Per the NEC there is no definition of control power transformer.

In general most manufacturers think of these points:
1)They are an open core and coil design, intended for mounting inside of a piece of equipment or a custom enclosure.
2)They are design to have very tight voltage regulation (often 90-95%) while suppling the inrush currents associated with starter coils and solenoids.
3)They are single phase.
4)They are almost never larger than 5000VA.
5)They are usually sized in VA not kVA.
 
Re: CPT

A transformer used in remote control wiring. Normally has a 120-volt primary winding and a 24-volt secondary winding. You can find one in your home for a doorbell. That would be only one of several examples.
 
Re: CPT

All good answers. The fist thing that comes to my mind is where a control voltage is needed to supply power to motor control devices such as contactors, starters, relays, pilot devices, pilot(indicator)lights, etc.
It is common for large motors to be 480v 3ph where the actual control you want to be 120vac max for the pushbuttons, pilot lights and coils. This is an example.
Not that this one that I found is marker CPS for control power transformer(X) which I found to be unusual when it is normally referred to as a CPT.
Even medium voltage motor starters us CPTs to transform 2300v or 4160v to 120v for control voltage.Motor control cicuit.
 
Status
Not open for further replies.
Top