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Most of the E-stops are rated at 10A or less. The following blog has explained how to wire an emergency stop http://www.ehow.com/how-does_5151421_do-emergency-stop-buttons-work.html. Wiring an E-Stop

But from my understanding of this circuit, the E-stop is still in series with the power-supply. Given the fact that the amount of current most E-stops can handle is so less (~10A), How is it possible to wire them so that they can be used for high-current electrical system?

Also, by wiring the emergency stop in series with the main power source (batteries) would violate the safety principle that resetting the emergency stop should not by itself turn on the power again.

How to connect E-stop?

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    \$\begingroup\$ The E-stop circuit would normally be used to control a contactor (large relay) which would then control the power to the load. \$\endgroup\$ Commented Jul 29, 2015 at 15:31
  • \$\begingroup\$ Resetting the eStop would normally only re-apply power to the load if the start button was simultaneously held down or the relay/contactor contacts had been welded together earlier. \$\endgroup\$
    – KalleMP
    Commented Jul 29, 2015 at 22:15
  • \$\begingroup\$ An eStop is a safety device and while it could be wired into the solenoid circuit of the contactor only and only have to carry an Amp or two of current it fails on the safety aspect, if the contactor contacts should have welded together then removing the coil current may not interrupt the power to the load. If you use the eStop to disable the control gear then you must have very high specification control gear, putting eStop in supply wire is safest if you can get a high current eStop. \$\endgroup\$
    – KalleMP
    Commented Jul 29, 2015 at 22:18

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The simplest way is to use a contactor which has a set of auxiliary contacts. These contacts would be wired as shown in your figure, with an indicator lamp instead of the load. The load would be controlled by the main contacts.

Doing it this way, the e-stop only has to handle the contactor coil current, not the load current.

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enter image description here small load carrys a big load MCR RELAY is fused at one Amp and MCR contacts can handle larger current and be used for a M1 , quit drawing pictorials, learn to read schematics !

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