Old Electrical Equipment - Sangamo S29 electricity meter

Three phase, three wire kilowatt hour meter.

Exterior

This very large meter is a three phase, three wire model. Made by Sangamo Weston Ltd., model S29.

The meter is approximately 8 inches square (20cm), and 7 inches depth (18cm).

Exterior

The case is made from black bakelite, with two screws securing the front cover and another two for the wiring terminals cover.

One of the small spacers on the back has broken off.

There are six holes on the bottom edge for wiring - two holes for each phase. There is no neutral connection.

Front with and without cover

The front cover has three windows for the register, rotating disc and information plate.

The six terminals along the lower edge each have two screws. Wires enter from below.

The two small L shaped pieces of metal are the connections for the potential (voltage) coils. Removing the screw from these isolates the coils from the main terminals, so that equipment can be connected for testing purposes.

Front plates and top

Top dials

This shows a reading of 1 kWh.

As is common with this type of dial register, each pointer rotates in the opposite direction to the previous one.

Lower plate

Sangamo Weston Ltd., Enfield, Middx., Eng.
Model S29 Watthour Meter

3x10 Amps, 50 Periods, 3ph.3w.
3x400 Volts, 150 Revs / kWh
Form 2

No. T 17055

Potential coils

The potential (voltage) coils are contained in black cylindrical shells.

There are two coils, one on each side of the meter. Wiring is colour coded red and blue, for the red and blue phases respectively. The black wires connect to the yellow phase.

Current coils

There are two current coils, made from enamelled copper wire. These are of substantial thickness, since the full load current passes through them.

There are two coils, one for the red phase and one for blue. This meter has no neutral connection, so it is not necessary to have another coil for the yellow phase.