Voltage loss

[ibwev]

When I power the attached circuit, the sensor reduces the voltage to the contactor to 7.5 volts. This is not enough voltage to operate the contactor. I could not find a datasheet on the sensor to know if I could safely increase the input voltage. What is the best solution to get another 4.5 volts to the contactor? (Maybe connect the sensor to a transistor to power the contactor?)

 

[Misterbenn]

What kind of sensor is it?

A transistor might be one option, but I'd suggest that you might be able to get a different relay - one with a lower switching current perhaps.

 

[Reloadron]

I see a transformer with what I assume to be a single 120 VAC primary and I see two secondaries in series and labeled 12 VDC? I do not see any rectification where we get from the secondary AC to DC? As drawn the circuit won't work. As drawn I see AC going to whatever that sensor is. You will need to provide more information about the circuit.

Ron

 

[Mike odom]

I see a transformer with what I assume to be a single 120 VAC primary and I see two secondaries in series and labeled 12 VDC? I do not see any rectification where we get from the secondary AC to DC? As drawn the circuit won't work. As drawn I see AC going to whatever that sensor is. You will need to provide more information about the circuit.

Ron

Ron,
what you're seeing as the second secondary is actually the contactor he is talking about. The transformer is a 220 to 12VAC.

Need sensor part number.

 

[Reloadron]

Ron,
what you're seeing as the second secondary is actually the contactor he is talking about. The transformer is a 220 to 12VAC.

Need sensor part number.

Thank you. The circuit as drawn made no sense to me. ? I still don't get the DC part? Where would DC come from?

Ron

 

[Mike odom]

who said anything about DC (except you, of course)???

 

[NorthGuy]

who said anything about DC (except you, of course)???

It says 12VDC on the schematics.

 

[Mike odom]

you're right, it does (guess I just ignored that)...

 

[Reloadron]

who said anything about DC (except you, of course)???

Mike, I see VDC plastered on the drawing at least twice. So we have no clue if the contactor coil is 12 VDC or 12 VAC? We also have no clue what the sensor that is in series with the contactor coil is? We also have no clue what the contactor coil rated current should be? Anyway, besides me I would have to say the original poster said something about DC when it was plastered in the drawing.

Ron

 

[tronitech]

You cannot have 12VDC coming out of the transformer, it's AC. What sort of sensor is it? If it's a simple switch that closes then you are connecting AC across your contactor/relay coil. Is the contactor/relay coil rated for AC or DC. What voltage?