Q:

How to add an emergency stop switch in a circuit?

I am into a project, where I have made a a bot, which has a 6 degree of freedom robotic arm with four wheels. I need to add a kill switch that is connected to a relay, which stops all the 10 motors. I don't know the circuit connection between the switch and the relay which then goes to the motors. It is powered by a 24V battery.

A:

Sounds like you need to begin with a conventional latching stop-start circuit: -

So, the circuit above will have another relay contact that feeds 24 volts to all your motors and, when the circuit is first powered, the relay will not be energized. To energize it press "start". A relay contact latches the start button contact.
To de-energize press "stop". Stop switches can be a series of emergency stop switches wired in series with the stop button above.

A:

If you do not have much power storage other than the battery, the easiest way would be a normally closed latching switch, like the big red e-stop buttons, in series with the battery, you hit that and when what small amount of charge is left in the system is used, all the motors loose power, 
Just remember to place it somewhere you can get to no matter the situation, and with this method, you can have more than 1 of these in series. 
If you already have a relay that controls power to the motors, you would fit it in series provided you want the control circuits to remain powered.

