Relay clicks, but wire feed motor wont operate

If the wire feed on your Hobart 251 MIG welder won't stop when you turn it on, there could be a few possible causes. Here are a few things to check:

1. Check the trigger on the MIG gun: Make sure that the trigger on the MIG gun is not stuck or damaged. If the trigger is stuck in the "on" position, it will cause the wire to continuously feed.
2. Check the wire feed motor: The wire feed motor could be faulty or jammed, causing the wire to feed continuously. Try disconnecting the wire feed motor from the welder and see if the wire still feeds. If it does not, then the motor is likely the problem.
3. Check the wire spool: Make sure that the wire spool is installed correctly and is not jammed or tangled. If the wire is not feeding smoothly from the spool, it could cause the wire to feed continuously.
4. Check the wire feed control settings: Ensure that the wire feed control settings are set correctly. If the wire feed speed is set too high, it could cause the wire to feed continuously.

If none of these solutions resolve the issue, it may be best to contact a qualified technician or the manufacturer for further assistance.

Looking at the Hobart manuals, that is how they set them up at the factory.

One way to make a change to that is to wire in a solid state relay or solid state Triac and pick up an energizing voltage off of location RC2-1 or RC2-2 on the control board when the trigger is pressed, or as an alternate location from the feed motor through a resistor and rectifier. Once you know if the voltage goes low, or voltage goes high at your point of signal, you pick the contact you want on the relay so when the wire is feeding out, the gas is flowing. and when it is not feeding wire out, the gas is shut off.

Your Hobart has a Drive Motor Protection.The Drive motor protection circuit protects drive motor from overload. If drive motor becomes inoperative, release gun trigger and wait until protection circuit resets allowing drive motor to feed wire again. Or you can reset it manually by pressing the reset button located on the back welder. If these actions does not work then here's the part number for your motor:HOB 239696.Check our website for pricing you need to call since this is an old welder and pricing needs to be search at Hobart Co.
http://www.praxairdirect.com/webapp/wcs/stores/servlet/TopCategories1_10152_10051_-1

First take our the spool of wire, then without any wire restriction, disconnect the gun from the machine and bridge the trigger connection, if the solenoid valve opens then the motor shoulod run. If it does, then check the trigger on your gun, take it off and bridge the cables, if it runs then your trigger switch is faulty.

the electronic circuit is broken

If the machine has diodes check them. Also if it has a bridge rectifier check it. My 120 would not feed wire and the bridge rectifier was bad.

You do not indicate if the wire is already out of the nozzle. If not, commonly the wire can jab the side of the tube it runs through and cannot advance.

IF the wire is already threaded, then there MAY be a fuse to protect the motor.

The click MAY be the gas valve, or the relay driving the motor and/or the main transformer for welding current. The circuitry for these is relatively simple and a voltmeter is your friend to troubleshoot this.

try checking your heat selector switch. the pc board gets power from it. so the pc board relay may function (click) but have little or no power once the curcuit is made to the feed motor. it happened on my 135.

First, UNPLUG the Welder! There is a small control board (2"x2") that the feed motor plugs into, it has a fuse on it. Here is what you do: Follow the circuit board trace that goes from one side of the fuse though a resistor then to the connector full of wires on the edge of the board, check that resistor for continuity it should read some value besides open. If it is open, this is your problem (as the drive motor ages it draws slightly more current than new, which should blow fuse, but instead blows the resistor). The resistor should be replaced with same resistance value, if problem persists replace again but instead of 1/4amp bump up to a 3/4amp for $1 or replace that drive motor for $150, you choose. Good Luck!

NOTE: As with any circuit board, take precautions to prevent ESD damage to board.

A schematic would certainly help, give Hobart a call and ask for a wiring diagram. or manual. Hobart are very helpful and may even give you guidance, you may have to pay the postage, they usually fax these documents so it will not cost you anything.