What is a Stamford DM110 AVR?

The DM110 AVR is the first Stamford Digital AVR automatic voltage regulator, used on the Stamford AVK range of AC alternators. These alternators are coupled to diesel engine brands worldwide to produce diesel generators.

The DM110 is is excited using a Permanent Magnet Generator (PMG). It also operates 3 Phase Sensing. Voltage sensing on all 3 phases. Useful when there are separate 1 phase loads of different magnitudes connected to a 3 phase alternator.

This AVR has Paralleling Capability.  It is able to allow the alternator to synchronise with
other alternators, operating in parallel using Droop CTs.

The AVR on a diesel generator is used to maintain the voltage during steady state loads and transient conditions when load is applied or removed. You can read about the effect of applying load to the alternator.

What protections does the Stamford MX341 have built in?

The DM110 has Over Voltage Protection.  This prevents alternator damage if the voltage exceeds a pre-set limit, such as with a grid connected application.

Sustained Short Circuit due to the excitation system. With PMG or Auxiliary Winding Excitation; gives the alternator a current ‘forcing’ capability to ensure accurate circuit breaker activation in a fault situation.

The DM110 has "under frequency roll off" (UFRO) as standard. The AVR incorporates an under-speed protection circuit which gives a volts/Hz characteristic when the generator speed falls below a pre-set (adjustable) threshold known as the "knee" point.

Over-excitation also comes as standard on the DM110.  This prevents alternator damage if the pre-set maximum excitation levels of current are exceeded.

The DM110 also has Under Excitation Protection.  This prevents alternator damage, caused by possible pole-slipping, if pre-set minimum excitation levels of current are exceeded.

It also benefits from loss of sensing protection in the event of a problem with the sensing circuit.

Where can I get its technical specifications?

You can download the technical specifications of this DM110 AVR below.