Supply For Spring Charging Motor

There will be an auxiliary supply, quite often DC with a battery backup. This is used for the motor and other aux devices like shunt-trip coil, closing coil etc.

Dear Sir,

Thanks for the reply. However, it is specified as 230V AC supply for the spring charging motor by the manufacturer. Kindly advise.

Sure, 230V AC is also a preferred aux supply. As you must be aware, this can be taken from the single-phase domestic lighting supply that will be available at the substation. However, i would strongly recommend the use of a normal UPS as a backup in the event of aux power failure.

110V DC motor is used for VCB of 12000V,2120 KVAR.

The type of voltage (AC or DC) and the range of the voltage (generally 220V, 120V, 110V, 24V etc.) for the VCB spring charging motor (as well as the control power supply for closing coil, tripping coil etc.) are indicated in the VCB data sheet. In most cases, there is the option to choose this voltage at the time the VCB is purchased.

The spring charging voltage and the control voltage are generally supplied from the DC source (Battery charger and batteries system) or the UPS system or at least some sort of reliable source so that the supply is guaranteed all the times (especially the control supply). However, in almost all types of CB, there is manual charging option so that the spring can be charged manually when no power is available (especially for maintenance purposes). Keep in mind, the spring that we are talking here is the closing spring. The tripping spring is automatically charged when the beaker is closed. If you are interested about the CB operating mechanism, see this thread: http://cr4.globalspec.com/thread/39932/Breaker-closing-and-tripping-mechanism

Note: I intentionally mentioned this thread here because I described the CB operating mechanism as simple as possible there in comment # 1. I can bet, it is rare available in any document. In my early career, I was involved with the maintenance of CB operating mechanism and figured it out after doing lot research to understand how the mechanism works.

- MS

I've only being involved with solenoid closing mechanisms. Any that involved distribution equipment had a DC supply from a battery bank, others for motor starting etc. were DC but mains supplied via a rectifier.

Relying on an external AC source with no UPS facility seems foolish to me.

The battery supply can go wrong as I found out, some clown had turned off the battery charger! Result dip in supply, main breaker to one section of the board tripped on UV. Unfortunately the charger was fed from that section. Couldn't close the bus section because the batteries were flat. I had to borrow batteries off 11 cars and vans to get us away!

Hi Dear Friend,

There is an auxiliary supply at your Recveiving Station which is provided through a dedicated Auxiliary Transformer installed at the station. Typically an auxiliary transformer is 33KV/415V. The 230V AC output is used generally to supply to the Induction Motor which is used to turn the gear system to spring charge the Breaker.