Automatic Transfer Switch

You can purchase a time delay relayl Check this one.

http://documents.tycoelectronics.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=1308242_CLCU&DocType=DS&DocLang=EN

Thanks Wareagle,

I have gone through the link you provided. What I need is a situation where by the NO contacts that closes by energising the coil to remain closed for like 3s after removing the voltage supply to the coil.

Thank you once again.

Hi my name is kemron ,seeing that the relay functions perfectly ,the next step you should take is ohming the relay.then connect an ammeter in series to analyzed the flow of current through the coil.once you obtain those readings .using the equation V=IR calculate the voltage or use a volt meter.after obtaining these values the capacitor you should obtain must be 4 to 6 volts above the circuit voltage rating . this would ensure that the charge in the capacitor can run even after the main supply to the relay is cut off.NB the uf value of the capacity should be around 3000 to 5000 uf.

Thanks,

But how can I do the ohming?

Thanks.

Capacitor discharge curve is exponential and the rate is dependent on the load. See this link for Capacitor discharge curve.

Quote EnB "I have gone through the link you provided. What I need is a situation where by the NO contacts that closes by energising the coil to remain closed for like 3s after removing the voltage supply to the coil."

The relay listed at the site I gave you will do this. It is adjustable through a s number of time delay settings.

Thanks to all of you. I will try it and get back.

Best regards.

Hello EnB,

Instead of putting such a big capacitor directly on relay you can do it just by putting small RC on driving CKT.As shown below.

The most reliable and simplest form of this is called a Pneumatic Off-Delay Timer with Normally Open Timed Contacts (or a TDR with what is called a NOTO set of contacts). NOTO stands for Normally Open, Timed to Open. They have a simple little bellows that operates the contacts. On energization, the contacts close immediately. On de-energization, the contacts stay closed until the air leaks out of the bellows, the amount of time is adjustable but can be ordered to be anywhere from fractions of a second to hours. Once the bellows exhausts, the contacts re-open. They make them electronically as well, but the control circuit is generally more complex for the casual user, as you appear to be. there are newer capacitor based TDRs now that duplicate the simplicity of the pneumatic relays, but the time ranges on them are rarely over a second (I might be wrong on that however). Stick to the old-fashioned pneumatic type and you will be fine.

In Canada it is illegal to use an uncertified unapproved device.

If it is found on your system , the minimum is a device removal, and you may find yourself being fined. If anyone is injured it will be treated very severely.

ATS for small systems are inexpensive. Why tempt fate?

I can actually afford to buy it off the shelf. But I want to do it myself so as to develop some pratical skills. Moreso, In my country, we dont have such regulations that restricts the use of locally made appliance like the ATS.

Thanks

You may want to investigate the use of mechanically interlocked contactors or "walking beam" interlocked breakers for the the transfer mechanism with break before make feature. This guarantees that your generated power and the utility remain isolated from each other.

A 3-phase electric motor reversing contactor is good for providing mechanical isolation.

Yes

EnB

Gen Tran boxes are readily available and safer than a home made system. Totally purchased systems (including the generator) usually have a 12 V battery and charger as the control power for the programmed test or actual power outage. If you don't want to buy a system and are legally permitted at your location, it is best to copy what is already successful.

Dear EnB,

The suggestion from Rakesh is the best and doable solution for your problem. I have done it many times, it works great.

All you have to do is to get a standard 12V DC relay (5 Pins) which comes usually in 400 ohms coil resistance and the schematic shown by Rakesh to drive with, then the contacts of the said relay will do the job for you.

I believe that will definitely solve your problem....;)

BTW, I have the same situation as you have and planing to assemble an single phase ATS panel by myself with magnetic contactors, timers and interlocking relays.

It will be a great help if you could share your wiring plan of the ATS panel you have designed yourself.

Have a nice day!

/M. Jawed/