(2012?Foshan) Figure for an electric sliding door part of the control circuit and working principle schematic diagram, A for the motor, c for the electromagnet, D for the armature, E for control

(1) automatic sliding door closure needs motor work to pull the pulley, so the switch should be closed to turn on the circuit, so that the electromagnet is energized to produce magnetism, attract the armature, so that the motor circuit is in the working state;

(2) the power of the motor work P = UI = 220V × 1A = 220W,

Because of the motor's internal resistance to heat, according to the Joule's law Q= I2Rt, the heating power P =

. tr>

I2Rt

=I2R,

∴The motor's internal resistance to the heating power of P1 = I2R = (1A)2 × 5Ω = 5W;

(3) part of the electrical energy consumed by the motor work due to the motor's internal resistance to heat and consumption, so the motor on the sliding door to do work power: P2 = P-P1 = 220W-5W = 215W;

So the motor on the sliding door to do work for: W2 = P2t = 215W × 2s = 430J;

Then the pull on the sliding door of the tension force F=

430J

=215N.

Answer: (1) For the automatic sliding door to close, switch B of the control circuit should be closed;

(2) The power of the motor when it is working is 220W; The power of the motor to generate heat is 5W;

(3) During the complete closure of the motorized sliding door, the pulling force on the sliding door needs to do 430J of work, and the pulling force on the sliding door is 215N.