Watt-Hour Meter Structure of Induction Type Relay:
The general arrangement of watt-hour-meter structure of induction type relay is shown in figure. It consists of a pivoted aluminum disc arranged to rotate between the poles of two electromagnets. The upper electromagnet carries two windings, the primary and the secondary.
The primary winding carries the relay current I1 while the secondary winding is connected to the winding of the lower magnet. The primary current induces emf in the secondary and so circulates a current I2 in it.
The flux Ï•2 induced in the lower magnet by the current in the secondary winding will lag behind Ï•1
by an angle α. The two fluxes ϕ1 and ϕ2 differing in phase by α will produce a driving torque on the disc proportional to ϕ1 ϕ2 sin α.
0 Comments