Voltage Regulators and Stabilisers - A comparison between Solid State and Servo

A Choice between Solid State & Servo-type Automatic Voltage Regulators (Stabilisers) 

Voltage regulators stabilise the voltage when it fluctuates, up or down. They are essential whenever reliable power is needed or when normal operation of electrical or electronic equipment is disrupted by the variations.

An ideal solution would be a fit & forget solution. One that requires no maintenance and no human intervention once installed. It should be an extension of your normal electrical infra structure.

Solid state stabilisers are just that, SOLID STATE. No moving parts, and no maintenance will be required. Servo stabilisers however, contain a motorised element. A motor has carbon brushes and these can get eroded or even dust and particles can interfere with their normal operation. They require regular attention and maintenance. Not a fit & forget solution. 

Servo stabilisers are very old technology. By the inherent nature of their design, they provide a fine output control. Their output accuracy is often as tight as 0.5% but is this essential? No! Most electrical utilities around the world can not provide or promise better than +-/5%. 

Historically, the voltage supplied in the UK (which is one of the best around the world today)  is set at 240V and the supply range is between 226-254V.  Many electrical distribution networks have been put in place to deliver electricity within this range.  Since 1995, steps have been taken to harmonise the UK’s supply specification to 400/230v -10% +6%, which is close to Europe’s supplied voltage.  This remains the current UK position.

Electricity Quality and Supply Regulations (EQS) will harmonise the supply across Europe at 400/230 +/-10% (253V-207V). EN 50160 states that voltage can vary around the nominal voltage in a band of +/-10% for minimally 95% of the time (measured with 10-min integration interval). For LV customers only a 100%-of-time limit is set at +10%/-15% of nominal voltage. 

So why insist on +/-1% or better...No reason whatsover. Most electrical and electronic equipment have a tolerance of far greater than this.

Here is a general comparison of the two different technologies;