Arb dual compressor burning fuses

[marcz]

Dear hi, It’s Marco from Saudi, happy to join you in this forum!

I’m looking for advise for an issue with my arb dual compressor. It seems to overdraft current while under maximum pressure. In the photo you will see the reading just before faulting (fuse burnt). I also attach a video link (Reddit) of this whole faulty process. Thank you!
Faulty compressor

 

[marcz]

Faulty arb compressor video

 

[Land Shark]

I would reach out to ARB's tech support. They are always really helpful

 

[peesalot]

Have you tried each motor separate ? Sounds like 1 motor has a short that appears once heated up or brushes are cooked.

 

[peesalot]

Crack that motor open & see.

 

[TreadingLight]

If you have resistance in a connection or a weak alternator it can lead to voltage drop at the motor and higher current draw.

I use a different model compressor but at low idle it would draw too much current and trip the circuit breaker. I solved it by idling up when airing up.

 

[discoverydave]

Had a similar situation on a dual CKMA12 setup I installed on a 100-series — at max pressure the amp draw spikes hard and if your wiring isn't up to it the fuse cooks. Two things to check first: what gauge wire did you run to the compressor and how long is the run? ARB specs 6AWG for the dual and a lot of installs I've seen cut corners with 10AWG, which is fine until the motors are both loaded up at once.

Second thing — voltage drop at the compressor under load. Get a multimeter on the power terminal at the compressor while it's running. If you're seeing below 12V under load, the fuse isn't really the problem, it's just the symptom. Could be undersized wire, a loose connection at the battery, or a weak ground. Fix the voltage drop first and the fuse issue usually sorts itself out.

If wiring checks out fine, then yeah, one of the motors may be getting tired internally — ARB's tech line in the US is actually pretty solid for diagnostics.

 

[discoverydave]

Had a similar situation on a dual CKMA12 setup on a 100-series. At max pressure the amp draw spikes hard and if your wiring is not up to spec the fuse cooks. Two things to check first: what gauge wire did you run to the compressor and how long is the run? ARB specs 6AWG for the dual and a lot of installs I have seen cut corners with 10AWG, which is fine until both motors are loaded up simultaneously.

Second thing to look at is voltage drop at the compressor under load. Get a multimeter on the power terminal while it is running and pumping hard. If you are seeing below 12V under load, the fuse is just the symptom. Could be undersized wire, a loose connection at the battery, or a weak ground. Fixing the voltage drop usually sorts the fuse issue.

If wiring checks out fine, then one of the motors may be getting tired — ARB tech support is actually pretty solid for diagnostics on this.

 

[discoverydave]

Had a similar situation on a dual CKMA12 setup on a 100-series. At max pressure the amp draw spikes hard and if your wiring is not up to spec the fuse cooks. Two things to check: what gauge wire did you run to the compressor and how long is the run? ARB specs 6AWG for the dual and a lot of installs I have seen cut corners with 10AWG, which is fine until both motors are loaded up at the same time.

Also check voltage drop at the compressor under load. Put a multimeter on the power terminal while it is running at max pressure. If you are seeing below 12V under load, the fuse is just the symptom not the cause. Could be undersized wire, a loose connection at the battery, or a weak ground. Fixing the voltage drop usually sorts the fuse problem.

If wiring is all good and correctly sized, then one of the motors may be getting tired internally. ARB tech support is solid for diagnostics on this stuff.

 

[discoverydave]

The wiring gauge point is the big one — I've seen so many installs where someone ran adequate wire to the fuse block but then used a cheap inline fuse holder with corroded contacts and that's where you lose 0.5-1V right there. Clean connections all the way through.

One more thing worth checking that doesn't get mentioned enough: the pressure switch itself. On older dual setups the pressure switch contacts wear and start arcing, which shows up as intermittent high draw right before cutoff. If the motors are cycling on and off at pressure instead of a clean cut, that's your sign. ARB sells the switch separately and it's a cheap fix relative to swapping motors.

Also, if the unit has done a lot of hours in hot climates — and Saudi is about as harsh as it gets — the motor brushes wear faster and uneven brush wear causes current spikes. Crack the motor end cap and check brush length. If you're under 6mm you're running on borrowed time.