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[This question has been completely re-written since originally asked.]

This circuit:

schematic

shares its power supply with a motor connected to CN1 NC relay contact. On power-on the motor runs for about 0.5 s until the circuit energises the relay and disconnects the motor. How can I prevent this brief motor operation on power-on?

DC motor specification:
12 V, 200 mA but under load it will draw up to 1 A.

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    \$\begingroup\$ @newbie: I think what this question is really about is, "This circuit (show original current sensing schematic) shares its power supply with a motor connected to CN1 NC relay contact. On power-on the motor runs for about 0.5 s until the circuit energises the relay and disconnects the motor. How can I prevent this brief motor operation on power-on?" If this is correct then please do a major edit on your question. If it's not correct then please do a major edit on your question. \$\endgroup\$ – Transistor Jan 11 at 15:18
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    \$\begingroup\$ @newbie - From your edited schematic, I'm assuming that you are using a module which you have purchased, and want to know how to modify it. That's simple - you cannot. However, what you can do is to buy another module, modify it by adding a cap between pin 2 of the 3140 and ground, then connect C1/NO in series with your other set of contacts. A capacitor of about 100 uF should give about what you want. In effect, you use the second module to delay applying power to the load until the first has recovered from its start-up transient. \$\endgroup\$ – WhatRoughBeast Jan 11 at 15:29
  • \$\begingroup\$ @newbie - Sorry, no. I've included connection points in my original comment. Do your own schematic and think for yourself. With all due respect, if you don't understand how a resistor/capacitor charges up, I don't see how I can explain it terms which will make sense to you. Good luck. \$\endgroup\$ – WhatRoughBeast Jan 11 at 15:43
  • \$\begingroup\$ Use the normally open contacts instead of the normally closed, and change Q1 to a PNP transistor so it energizes the relay when the comparator output is low. Unless of course there are other constraints that you haven't told us about... \$\endgroup\$ – Elliot Alderson Jan 11 at 16:12
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    \$\begingroup\$ Why can't you swap them? This information should have been part of your original question. OK then, just put another relay with the coil in parallel with RE1 and use the NO contacts of the second relay. \$\endgroup\$ – Elliot Alderson Jan 11 at 16:39

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