PG1995
Active Member
Hi
Q1: I have been tying to get a mental picture of what is being said above. Could you please help me with it ? Like some simple diagram, applet, etc. although I have tried it myself without any success.
Q2: Do you need to feed the electromagnet with a pulse of DC permanently in order for wipers to maintain their position? If you don't need to apply the pulse permanently, then how does the electromagnet shift (step down) the wipers to some lower position from higher position? Thanks.
Regards
PG
An electromagnet advances (steps) the wipers to the next position when fed with a pulse of DC. The magnet's armature (spring-loaded) operates a pawl that advances a ratchet. When the pawl reaches its full stroke, it blocks the ratchet so it and the wipers will not overshoot. When power to the coil disconnects, the spring retracts the pawl. Another pawl pivoted on the frame ensures that the wipers do not move backward; contact friction keeps them in place. Some uniselector designs step on application of the operate pulse; others step on its removal.
Reference: https://en.wikipedia.org/wiki/Stepping_switch
Q1: I have been tying to get a mental picture of what is being said above. Could you please help me with it ? Like some simple diagram, applet, etc. although I have tried it myself without any success.
Q2: Do you need to feed the electromagnet with a pulse of DC permanently in order for wipers to maintain their position? If you don't need to apply the pulse permanently, then how does the electromagnet shift (step down) the wipers to some lower position from higher position? Thanks.
Regards
PG
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