Western wideout melted power cable

Hydromaster

PlowSite Fanatic
Location
406
Every time the electric motor pump motor draws 50A + or - the battery’s voltage will drop he needs to have the same supply voltage all the time so he can test the drop in voltage. He’s not testing the condition of his battery.

He’s not testing just the motor for the plow pump.

I don’t necessarily think this test is even necessary find the root of the problem,
Necessarily.

is the op deadheading ,, holding on to a function after it’s completed ,
Running on bypass. This will heat things up too. ( just a example)

what if this was a 110v system or a 12volt system without a battery ?
 
Last edited:

Mountain Bob

Senior Member
Every time the electric motor pump motor draws 50A + or - the battery’s voltage will drop he needs to have the same supply voltage all the time so he can test the drop in voltage. He’s not testing the condition of his battery.

He’s not testing just the motor for the plow pump.

I don’t necessarily think this test is even necessary find the root of the problem,
Necessarily.

is the op deadheading ,, holding on to a function after it’s completed ,
Running on bypass. This will heat things up too. ( just a example)
I explained the proper "voltage drop" test, which is the industry standard for locating a problem in a conductor or connection.
Measuring a "drop in voltage" is pretty useless in DC, especially with high draw devices, of course there will be a drop, which makes it mostly useless. Although a huge drop may indicate a big problem, like a conductor too small.
 

Hydromaster

PlowSite Fanatic
Location
406
If you make multiple tests with a fixed amount.
Like a bucket full of electricity, every time
You use some there is less in the bucket.

first test 12v
Now because there is less in the bucket a second test can’t have 12 as we used it ,
Now it will have 11.9 A voltage drop not related to the circuit.

When you place your meter "across", or in parallel with the circuit you are testing, you are providing another path for the voltage to travel. If there is excessive resistance then your meter becomes "the path of least resistance" and you will register a voltage reading. If the circuit is functioning properly all voltage will pass directly to the load and your meter will register an acceptable reading. "Acceptable" for most circuits is less than .4 volts, although .1 volts or less is preferred.
Seeing as we have a motor that is like a starter , seeing .6 volts during a voltage drop is expected

also while we’re at it
First check the entire positive side of the charging circuit for excessive voltage drop. Hook your meter's positive lead to the alternator output stud and your negative lead to battery positive post. Run engine at 2,000 RPM with all lights, blower motor, radio etc. on and check voltage reading on meter. Leave the rear defroster off during this check as it may create a unusually high read. An acceptable reading is .5 volts or less. If you have an out of spec. voltage drop, check connections at alternator and battery as well as for an use of undersized cable. Check the negative side for the charging circuit the same as the positive with your meter's negative lead on the alternator case, or ground strap if equipped, and the positive lead on the batttery negative post. Voltage drop on this side of the circuit should be .2 volts or less. If it's not you know what to check and how to check it!

ps Bob, I agree it’s hard to test a starter with the engine running. For that test you will need to start with the engine off.
 

Hydromaster

PlowSite Fanatic
Location
406
Because ground circuit voltage drop can cause most of the symptoms listed earlier, consider adopting this new work habit: test grounds first. Before you do a tune-up, check out electrical problems, or test a starting, charging, ABS, or air conditioning system, routinely test the engine and body grounds. Connect your digital multimeter between the engine and negative battery terminal. Safely disarm the ignition and crank the engine for a few seconds, or if your multimeter has a data recording function it will capture the reading in as little as 100 milliseconds.

If the voltage drop is excessive, repair the engine ground circuit and retest. Note that on some ignition systems without a distributor, the simplest way to prevent the engine from starting during the ground test is to pull the fuel pump fuse. Next, connect the digital multimeter between the negative battery terminal and the vehicle’s firewall. Then start the engine and switch on the major electrical accessories. If there is too much voltage drop, then fix the body ground and retest.

Once the engine and body grounds are within limits, proceed with your diagnosis. Do not be surprised if fixing these grounds solves the car’s problems. The fact that a vehicle passes the body ground test does not mean you can safely ground your digital multimeter wherever you want to. Some technicians have run in circles for hours because their digital multimeters were not well grounded. For safe electrical service, make yourself a 20- or 30-foot jumper wire with an alligator clip on each end, allowing you to test an electrical fuel pump, lighting system or ABS computer in the rear of the vehicle by grounding your digital multimeter to the battery with the jumper wire.
 
OP
M

MarshallTT

Junior Member
Location
Minnesota
A lot of info but I think I got a place to start now. I did before I went home for the weekend run another plow on the same truck and I ran my same load test on it and it never got hot just warm. So I'm thinking it is the ground on the plow.
 
OP
M

MarshallTT

Junior Member
Location
Minnesota
A lot of info but I think I got a place to start now. I did before I went home for the weekend run another plow on the same truck and I ran my same load test on it and it never got hot just warm. So I'm thinking it is the ground on the plow.
Oh and i should mentchen that i noticed a difference in speed the plow moved when testing the other.
 
OP
M

MarshallTT

Junior Member
Location
Minnesota
So same truck different plow....

New plow was better then plow in question?

Can you do the same with different truck ?
Yes. same truck different plow worked good. If the crew leaves me a another truck then I will test the plow with the problems to better rule out the truck as a cause.
 
OP
M

MarshallTT

Junior Member
Location
Minnesota
I tested plow with one of our 550s instead of the 250 I was using and plow works great, its full speed is back and after about a minute of load testing up L R down etc cables are cold. So I think the lazy option is too assign the plow to the truck it works with. But that might bite me in the ass if it breaks down and the driver drops of the broken one in my shop and picks up the next plow in line to finish his route and that one doesn't work also. So i will see if I can do a voltage drop test on the 250 and upgrade the ground wire.
 

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