Branson 6530C seems to be hot under the hood

[dclt736]

To measure the load, i was just going to remove the relay and use a multimeter between the power in and out terminals with the tractor running and AC on. I will also load some of the other circuits within that relay block and see if anything changes. I will have a lot more information and images this evening. If the current draw is low, then maybe the wire terminal might be the cause, but the odd thing is this is the circuit i moved to a new panel and it is that same relay now melting the plastic of the housing, so acting like a high load. But it is also only on one side of the relay that is getting damaged, and if high current why not damage/heat on both sides?

 

[Slowpoke Slim]

It's probably on the contactor side of the relay, not the coil side. Normally a coil on a relay will draw next to nothing for current.

It's the switch contactor side that's drawing the current.

 

[dclt736]

So I was able to do some load testing and heat testing.
So with the tractor running for about 10 minutes after sitting a day, with the hood open, the load going through the AC/Fan relay ranged for a low 8 amps with the fans on low and a high of 13.5 amps with the fan on high. With the AC turned off, but fans on high the load dropped to 11 amps. So that does seem out of line to me, and the circuit is fused at 30 amps, but I think i will change that out for a 20 Amp.
The temperatures are more interesting.
I used an infrared thermometer to check at this point.
The muffler was showing 130F, the heat shield between it and the relays was 99F and the tops of the different relays showed a range of 95 to 110F.
I then closed everything up as normal and went out with an 8 foot bush hog and mowed down some pasture for 35 minutes.
Once back to the yard, the muffler was showing 230F, heat shield was 145F but the relays has really climbed, the AC/Fan case was now up to 150F, but the back up system relay and other had climbed even further they were at 190F.
So not sure if that is due to trapped exhaust heat or electrical issues.
Everything electrical works as it should, and the battery and charge system seem normal as well, no charge indicator light on.

This image shows the original fuse and relay boxes (top two) and the bottom relay/fuse box is what i added to split the loads some. You can see the very right relay spot on the middle box is melted, that was where the AC/Fan relay was from the factory.
Below shows the same thing happening on the new box.

When i created the new fuse box, all the power wires are 12 gauge in it, all the coil wires are 16 gauge.
I need to trace the wire that has heated to see if it is on the supply side or the load side, it does go to the fuse but i cannot recall if i wired it fuse, relay, load, or Relay, fuse, load.
Tractor is going to a local shop for AC testing as the system does blow warn air after being on for an hour or so when it is hot.

 

[Branson Bob]

To measure the load, i was just going to remove the relay and use a multimeter between the power in and out terminals with the tractor running and AC on. I will also load some of the other circuits within that relay block and see if anything changes. I will have a lot more information and images this evening. If the current draw is low, then maybe the wire terminal might be the cause, but the odd thing is this is the circuit i moved to a new panel and it is that same relay now melting the plastic of the housing, so acting like a high load. But it is also only on one side of the relay that is getting damaged, and if high current why not damage/heat on both sides?

Others will correct me if I'm wrong but you cannot typically run a current through your multimeter. It's a measurement circuit and cannot handle full load current traveling through it.

If you put the test probes in series with the circuit so that the circuit runs through the meter it might blow a fuse and/or create quite a spark. You can test voltage running through a multimeter but not current.

 

[Cougsfan]

It's probably on the contactor side of the relay, not the coil side. Normally a coil on a relay will draw next to nothing for current.

It's the switch contactor side that's drawing the current

You are correct Slim. The secondary or contactor side is the load side and usually will have the highest amperage. That's what a relay is for, to avoid running high amperage through the system' controls. However if there was a short inside the relay, it could overheat without the load side showing excessive amperage.

Others will correct me if I'm wrong but you cannot typically run a current through your multimeter. It's a measurement circuit and cannot handle full load current traveling through it.

If you put the test probes in series with the circuit so that the circuit runs through the meter it might blow a fuse and/or create quite a spark. You can test voltage running through a multimeter but not current.

Most multimeters do have the capability to measure amperage, but it requires disconnecting the circuit and running it in series through the multimeter, which is inconvenient, very difficult and sometimes unsafe to do because of sparks. I have only done it on circuits that pull milliamps. Clamp meters are much more practical tool to measure amperage

 

[dclt736]

The current test was very easy to do, i removed the relay and used the probes of the multimeter to into the wire terminals.
It should work all right, as the digital meter showed the currents ok, without any damage.
The meter i have and most have this has a special probe connection on it for load, and i assume the tool is designed to protect itself.
My meter was rated to 10 amps, so i was a little over that, but seem to be ok.
I am trying to understand why one terminal on the power through terminals would get so hot, but the other terminal not to show any issues.
This has happened in both fuse boxes so there is something i do not understand about the current flow and the contacts.

 

[Cougsfan]

Not exactly sure of what you are describing. Here is a simplified diagram of how a relay works. It is essentially two circuits. A low amperage circuit for controls (such as the switch for the lights) has a coil that energizes a higher amperage circuit for the device (such as the lights themselves). Each circuit has a feed and a ground. Any one of those feeds or the ground, or the relay itself could be the problem.

 

[dclt736]

Thanks Cougsfan for the relay diagram, and i did the amp test by using the terminals of the High current side of the relay block.
I have the tractor in for AC testing now, and maybe they might have some information to give me as well.
I will try to make up a new wiring schematic of the changes I made, but it will be hand done, not the nice image you created, once the tractor is back home.

 

[5030]

One thing that owners who get a cab unit with AC don't realize and that is, besides keeping the refrigerant level up, you have to clean the evaporator and condenser units regularly and the under the top or under the seat (in new Kubota's) cleaning can be quite involved.

Don't care how good the cabin air filter is, the evap unit (and the heater core) will get gunked up. I clean mine every spring which on my tractor, entails removing the top and the blower housing, not an easy job but necessary unless you want to pay your dealer's shop rate to have them do it.

When the ac starts to have an odd smell, you can bet the evap unit is loaded with fine chaff.

 

[dclt736]

This is very true Super, and on the Branson, the oil cool, Condenser, and rad are in line and spaced very close together. They have a screen in front of of the oil cooler, and then a second screen in front of the rad, and it is surprising how much stuff still gets into them. Last year the water pump had to be replace and at that time the rad was removed and a good cleaning of the oil cooler and condenser was done. And I did a compress air cleaning already a few times this season, however it is impossible to see through the component with how this tractor is designed to get a good idea of the results of the cleaning.
The battery and air filter sit right in front of the rads as well , which further hinders any real good inspection and cleaning without doing a some form of a teardown. Knowing what I do now after owning a Branson for a few years, if I ever look to replace it, i will per buying on design and not on brand. The old hindsight is 20/20 comes to mind here.
And as a side note, i am working on two issues, one electrical which i started this post on and the second is that the system will blow cold air for a while but will at some point start to blow hot air. This does take some time to occur, often it being an hour or so. I will post the results from the AC tech once they get to looking at the tractors system.