Siemens 420 manual Sequence ➁, DC braking after external selection

3 Functions Issue 07/04

Sequence ➁

1.Enabled and selected using BICO parameter P1230 (refer to Fig. 3-52)

2.The inverter pulses are inhibited for the duration of the de-magnetizing time P0347.

3.The requested braking current P1232 is impressed for the time selected and the motor is braked. This state is displayed using signal r0053 bit 00.

4.After DC braking has been cancelled, the drive accelerates back to the setpoint frequency until the motor speed matches the drive inverter output frequency. If there is no match, then there is danger that a fault will be output as a result of overcurrent - F0001. This can be avoided by activating the flying restart function.

ON/OFF1
BI: Enable DC brk.		t
P1230.C	1
(0:0)	0
	f	t
		f_set
	f*
		DC braking
		f_act
		t
	i	P0347
		t
DC braking active
r0053	1
Bit 00	0	t

Fig. 3-52 DC braking after external selection

NOTE

1.The "DC braking" function is only practical for induction motors !

2.DC braking is not suitable to hold suspended loads !

3.For DC current braking, the motor kinetic energy is converted into thermal energy in the motor. If braking lasts too long, then the drive can overheat !

4.While DC braking, there is no other way of influencing the drive speed using an external control. When parameterizing and setting the drive system, then as far as possible, it should be tested using real loads !

5.DC braking is independent of the ON command. This means that it can even be selected in the "Ready" state.

MICROMASTER 420	Operating Instructions
124	6SE6400-5AA00-0BP0