Control wiring

T

Tudmutt

Member
Location
Iowa
Occupation
Electrician
Running into an issue. I called the control guy that did the wiring and he was no help so he gave tech supports number and they were no help.
I have a motor control cabinet that is suppose to send 24 volts dc to the motor starter to turn it on. This setup has been working for 3years and we just replaced the motor starter, didn't touch a single thing in the control panel, but can't get 24v to the starter now. We have the plc board talking to c678 which is working but we aren't getting any volts off the yellow wires which head to our motor starter. Appreciate any advice. 1000005233.jpg
 
T

Tudmutt

Member
Location
Iowa
Occupation
Electrician
hillbilly1 said:
The yellow wires are switch legs. Probably the power supply.
Click to expand...
They are supposed to be switch legs going to the terminal block which then sends signal to my motor starter. My dry contactor isn't the issue, but im still not getting volts going through it.
 
ptonsparky

ptonsparky

Tom
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
hillbilly1 said:
Is the overload block set on the starter? If it is tripped, you will not get a reading, providing the control power is hot.
Click to expand...
This ^, a coil is open, another contact is open or a wire is off.
Check your source voltage and work from there.
New starters usually need to have the overloads reset. Are the wires on the correct contacts of the overload?
 
P

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Whatever power turns on the motor starter comes in at terminal 677, feeds thru the relay contact and goes out to the ms on 677A (or vice versa).

You should read zero volts from 677 to 677a if the relay is on, and full control voltage if it is off or you unplug the relay.
 
T

Tudmutt

Member
Location
Iowa
Occupation
Electrician
TwoBlocked said:
Which wires go to the motor contactor. The red with black tape wire and the red wire on the middle bank, or the blue wire and white wire on the bottom bank? Notice that the red wire is on terminal 679, not 677A. Should it be?
Click to expand...
Both those reds goto the motor starter, but there's no power coming from those Yellow wires.
 
T

Teaser2

Member
Location
MDDENJ
Occupation
Electrician/EE
Assuming that you have the required power where it needs to be, no external circuits holding you up (PLC output etc.) , It appears to be that Output #10 needs to be on to pull CR676 in.

If nobody touched the wiring (sounds like you did not); possibilities are:
1-You installed a wrong starter in terms of the coil voltage
2-O.L contact needs to be reset if it is not part of the starter
3-PLC output is not turned to pull in the necessary relays

It is interesting how they used the color red (120V?) which confuses me. Yellow/Orange wires sometimes means that those wires are originated from another panel/location

Rockwell Connected Components Workbench (CCWB) is a free software; you can try to download it to connect the MIcro820 you have there, if that is holding you up.
 
T

Teaser2

Member
Location
MDDENJ
Occupation
Electrician/EE
Forgot to add: why did you replace the motor starter? Because of the fact that it was not pulling in to start the motor? If so, your problem was what you are facing now. If that is the case, you could have had (have) "external" , required interlock from devices, safety circuits, PLC conditions holding you back. These are just assumptions without being there to check everything and reviewing the complete schematics, PLC code.
 
S

scrubbin

Member
Location
PA
Occupation
maintenance Tech
Random ideas: disconnect the 24vdc coil wires off the motor starter then press motor start and see if you get the 24vdc on the disconnected wires.
Second idea to check: Check plc: Are you getting an input light on the pc when you press motor start button?
 
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