Blog posts of '2021' 'June'

If you are installing a standby generator on-premises with a mains power supply, it is a legal requirement to have a transfer switch. This can be either manual or automatic. This avoids the mains power burning out the generator which would be almost certain to happen if the mains power came back on while the generator was running, and it avoids the generator back-feeding the mains which would endanger the safety of the electricity utility workers.

Both types of switches perform the same function, but the automatic transfer switch obviously does it automatically, saving time and restoring power almost immediately. Furthermore, if you have a manual switch, it means that you have to be on the premises in order to start the generator, so if you are away there will be no power until you return and switch over.

There are two types of automatic transfer switches, or ATS, panels. One has mains detection built-in and monitors the mains supply. When it detects a mains failure it will send a signal to the generator to start. When the generator has started it then sends a signal back to the ATS saying that it is available, and the ATS will then switch to the generator.

If the ATS does not have mains detection built-in, this will have to be part of the generator and it will monitor the mains supply. When it detects the mains failure it will send a signal to the ATS to disconnect from the mains and start itself automatically. As soon as it is up and running it then sends a signal to the ATS telling it to switch to the generator.

There are a number of different designs of ATS panels, but usually, a mains failure relay is fitted with two contactors in an enclosure. The contactors are mechanically and electrically interlocked, and a mechanical device called an interlock ensures that the two contactors cannot be closed at the same time. If you have two contactors, A and B, the circuit to close contactor A is wired through the auxiliary of B, therefore when B is closed, it is not possible to energize A. The same is true for B which is wired through the auxiliary of A. This provides the electrical interlock.

When the mains fails and the generator starts, the ATS opens the mains contactor and closes the generator contactor. When mains power is restored, the reverse happens. Since the two contactors can never be closed together, there is always a short break in the supply as the contactors change over.

Almost every home in the country has electrical power, and most of the time we don’t even think about it and how it works. When we need light, we press a switch. When we need to cook, we press another one and turn some more on the cooker as required. That’s it. Simple.

However, in outlying areas the electricity supply can be intermittent on occasion, and although we don’t think much about it, if at all, power outages can happen anywhere at any time for any number of reasons.

Some of us are old enough to remember the 3-day week in 1973/1974 when the miners were on strike at the same time as there were oil shortages. There was insufficient fuel to run the power stations and Prime Minister Edward Heath announced that the lights would go out at certain times of day, and we can remember refusing to be crushed by the miners while we were decorating and continued to paint the lounge walls by candlelight in the evening.

The Christmas No 1 in 1973 was “Merry Christmas Everybody” by Slade, which was ironic, but we buckled down and got on with it. Comedian Bruce Forsyth said on TV “It could come to this”. He struck a match and announced: “Match of the Day!”.

Well, we survived all that, but there is still the possibility of power outages today, nearly 50 years later. This can cause problems ranging from inconvenience because the TV is not on and we can’t watch Corrie or East Enders, to serious issues where power is needed continuously such as in hospitals, for example.

This is why many people invest in stand-by generators so that if the power goes down the lights don’t go out – well only for a few seconds at most.

At Blades Power Generation we provide the best emergency power source in the UK with our range of generators which can be operated either manually or with the use of an Automatic Transfer Switch, or ATS.

When you use a manual switch, it obviously means that you need to be on the premises when the power goes down in order to switch over to the generator.

Using an ATS is the answer if you need to keep the power on even when you are away from your home or business, because it will automatically switch on the generator, which is the best emergency power source in the UK, and the lights are on again as soon as it is up and running, in a matter of seconds.