Response of thermal demand meters

THE TIME OF RESPONSE of demand meters is of critical importance wherever a demand charge is made for electricity. In demand meters of the mechanical block-interval type the demand interval is usually governed by a gear train and resetting mechanism connected with some synchronous device, such as a clock motor, and response time presents no special problems in design. The response time of thermal meters depends upon less easily evaluated constants and coefficients. This article examines these factors and presents equations from which the time of response may be calculated.