Maker Pro
Maker Pro

design motor protector

KUMARA SHP

Aug 1, 2014
122
Joined
Aug 1, 2014
Messages
122
I have attached photos I need to make the circuit for specified location
I need to turn off motor using relay when it draw more current
my problem is I have transformer to sense the current but it give 0.2VAc for 2A, can I make circuit that will sense 0.2VAC
I have idea with op amp to design relay to turn off the circuit for overload
thanksCIRCUIT_DIAGRAM_1.jpg
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
use a precision rectifier, then use this either raw or filtered to compare to a voltage reference (using a comparator) followed by either a latching circuit or a monostable to have the off time you require.

Note that startup currents are typically high, so an RC circuit to "average" the voltage over time will allow a short term overload as the motor spins up. Your choice of time constant will need either careful calculation or some trial and error.
 
Top