Help me understand this..Hobart

[Steve Crum]

I have a couple questions for you Hobart experts. Had My Hobart G3010 up and running this morning. Got the engine tuned in and running fine. This unit has the 'optional' engine idle control system on it. As it was, the toggle switch on the panel did nothing in either position, the engine ran at full governed speed. I suspect the small circuit box for this idle control is not wired up correctly or is bad I switched a ground wire so that the solenoid on the engine activates and de-actives with the toggle switch now and the engine idles or goes to full speed. Is this system supposed to allow the engine to idle at no load then kick up to full speed when a load is sensed?
Does anyone have a wiring schematic for this part of the system? I have all but this one.
Second question is on the weld voltage control, the black knob in the center of the amperage control wheel. It's my understanding that this is to control weld voltage. I have from 40 volts to 80 volts depending on where the knob is set. The odd thing is this seems to also control the alternator output voltage. I can set the weld volts at 80 and I will have 240 at the 40 amp plug, but when I set the weld volts down to 40, I only get 33 volts at the 40 amp plug. Why would the welding voltage control be also controlling the alternator output voltage? Is this supposed to be this way? or is it a problem in the machine?

[Steve Crum]

Spoke with Mike at C&M welding supply in Ohio today, real nice guy and very knowledgable on the old Hobart engine drives. He was able to send me a schematic of the Idle control system. He also stated that parts for this are virtually non-existant. One thing I found in the schematic is My machine has no load sensing capability, all or nuthin' baby! BUTTT.. whit the addition of a current coil with a reed switch and shunt in the main line from the brush holder to the control panel, this can have full auto load/speed control. All it needs is a sensing switch to sense the load and power the coil on the vacuum throttle. Anyone have an idea of what I could use for a load sensing switch from the after market? I'm told these parts are not available either. I don't need to stay original, I just want it to work.
On another note, I did score a real nice Bernard 3 gallon liquid cooler unit fro my Weldcraft WP 12-12 500 amp Tig torch today. Found this at the local scrapyard on another machine, cost less than the sales tax on a new one. Forgot the angle iron I was looking for!

[Some Creep]

Does the cooler work, or does it need a rehab too?

[Steve Crum]

Does the cooler work, or does it need a rehab too?
Looks to be in very good condition, I ran the pump tonight and it is quiet so I put a tee and pressure gage in the line and pinched the hose off and the pump developed the factory setting of 60 PSI without any leaks in the coil or pump. All I can see that it needs is a good wipe down with super clean or 409. I checked e-bay and this is going for $886.00 new, so I didn't do too bad for a Jackson.

[old fart]

All you need for a current sensor is a reed switch located near the reactor coil. These switches close when exposed to a magnetic field and are available at any larger electronics supplier.
O.F.

[Steve Crum]

Did some more looking per Oldfart. On the top of the reactor was a bundled wire, Closer inspection revealed the reed switch, a small glass tube with the contacts inside. By appearance this is a normally closed switch (or the contacts are stuck together?). I'm not positive how to test this switch or un-stick the contacts, but maybe I can pass it thru an energized solenoid valve coil. Any other suggestions? We are all learning something new today!
http://i6.photobucket.com/albums/y201/crumsteve/ASIDCP_0001-54.jpg

http://i6.photobucket.com/albums/y201/crumsteve/ASIDCP_0002-34.jpg

[Steve Crum]

Jake gave me 2 Norgren industrial reed switches today, one is normally open and one is normally closed. I'm of the assumption that I need the normally open switch. It would appear that without a load, the control reactor builds up a strong magnetic field which will hold the reed switch closed until a load is applied, the field in turn collapses thus the switch opens breaking the circuit and releasing the vacuum diaphram allowing the governor to take over until the load is stopped and the control reactor builds a field and the timing relay times out. Fascinating how a simple system like this works. One of the things I enjoy most about reviving older equipment is learning the technology of what makes them tick. Shame that my 19 year old son doesn't share this fascination.

[Pin Head]

It would appear that without a load, the control reactor builds up a strong magnetic field which will hold the reed switch closed until a load is applied.

It is the other way around: In the absence of current flow, there is no magnetic field in the reactor. When you are welding, it is magnetized.

[Steve Crum]

It is the other way around: In the absence of current flow, there is no magnetic field in the reactor. When you are welding, it is magnetized.
That makes more sense. That's likely why Jake gave me both NO and NC switches to see which one would work. Even Jake wasn't sure just how this system works. So hopefully between a snowplow mounting assembly and turkey dinner today, I can get a chance to tinker with this some. I.ll keep everyone posted. I've seen posts in this and other forums with basically the same questions that never did receive an answer.

[Steve Crum]

Well I changed the reed switch tonight, the new one even has a pilot light on it to tell when is made. The system still don't work. I opened up the timing module and the bottom of the printed circuit board has been wet and is corroded. I've already been told these are not to be had. Soo... looks like it's time for some farm ingenuity. I'm going to see if I can set up an 8 pin industrial timer and relay and make the relay with the new reed switch to latch the timer so it will drop out the relay and de-activate the coil on the vacuum unit. then when the reed switch breaks, the timer times out and activates the relay and powers the coil on the vacuum unit to idle the engine.
Sound like it will work?

[Steve Crum]

Here's how I ended up on the idle control. The Hobart timer was toast, so in the absence of replacement parts, I substituted.
It looks like a CF to the untrained eye but it's really simple actually.
http://i6.photobucket.com/albums/y201/crumsteve/ASIDCP_0001-56.jpg

This part of it is the 'brains of the operation, A Norgren industrial strength reed switch. Yes it does matter where it is located on the top of the reactor, where Hobart put their's was the right place to start.
http://i6.photobucket.com/albums/y201/crumsteve/ASIDCP_0002-36.jpg

In place of the Hobart timing module, I used a Potter & Blumfield 10 second adjustable timer/relay. Because this was all I had in the junk box and it is 120 volt operated, I had to have a source of 120 volt power to operate the timer side. Back to the junk box and found a 100 watt 12 volt to 120 volt inverter. Got his whole CF wired in and of course the vacuum servo coil still operates off 12 volts thru the contactor side of the timer and the system works great!
http://i6.photobucket.com/albums/y201/crumsteve/ASIDCP_0003-25.jpg
I know, it looks like somebody left their electric razor on the welder. But I'll get a 12 volt timer and the inverter will go away.
I did some "playing" around and vaporized 4 1/8" 7014 rods. Man can that cuss weld! 35 amps upto 300 amps steady as a rock. Now I can get the rest of it back together. May have a job for it after the first of the month.

[TommyA]

Steve, I have a old P&H engine driven that may need some work on the idle adjustment. The reason I say that is there is a string attached to the governer and it looks like it was placed there to throttle the engine up. I haven't found any info on this welder and probably won't but I almost bet that it uses something of the same system as yours. I may be calling soon.

[Steve Crum]

This was my initial learning experience with these