Fuses blowing in Control Box

Discussion about the CNC Shark Pro Plus HD

Moderators: al wolford, sbk, Bob, Kayvon

Post Reply
Timeless CnC
Posts: 1
Joined: Fri Mar 22, 2013 12:07 pm

Fuses blowing in Control Box

Post by Timeless CnC »

We have a CNC Shark Pro Plus HD and we blew a fuse during a 13 hour routing pattern (at 92% done). We replaced the router (2.25 hp Bosch) with a brand new one . We jogged it back into position and everything was ok. Then we "ran" the pattern. As soon as the new router turned on, the new fuse blew.

What could be blowing the fuses? We opened the control box and all the wires look good, everything is tight. Any suggestions to troubleshoot?

Thanks, Terry

SPH01
Posts: 91
Joined: Tue Nov 01, 2011 8:35 am
Location: Gavilan Hills, CA

Re: Fuses blowing in Control Box

Post by SPH01 »

Have you tried not running the router thru the control box?
What size fuse is in it and slow blow or standard. I know there were others on here with that issue.
What bit and how hard are you pushing the program? (loading the router will pull more current)
maybe a search under fuse will bring up the post.
Steve

Wolffie1
Posts: 270
Joined: Wed Oct 24, 2012 3:46 pm

Re: Fuses blowing in Control Box

Post by Wolffie1 »

I am runnung a 2.5Hp AEG router on my HD and have never blown a fuse (touch wood).
Sounds like the new router is faulty and overloading the circuit.
Cheers
Wolffie

rungemach
Posts: 460
Joined: Mon Aug 02, 2010 8:24 am
Location: Sarasota, Florida

Re: Fuses blowing in Control Box

Post by rungemach »

You might find this thread helpful.

http://www.cncsharktalk.com/viewtopic.p ... hilit=fuse

The fuse is sized less than the rated current of your router at full load. That fuse is fine for small routers like the Colt , but less so for the larger routers.
The larger routers do not draw full amps unless they are cutting hard, so NWA is viewing this as a "feature" so you don't cut to aggressively...

Upsizing our fuse value slightly may prevent nuisance blowing. You may want to get the NWA blessing on a new fuse value for warranty purposes.

jeb2cav
Site Admin
Posts: 1524
Joined: Thu Sep 30, 2010 7:04 pm
Location: Kentucky
Contact:

Re: Fuses blowing in Control Box

Post by jeb2cav »

I'm more inclined to say this is a sign that the router is defective, or something about it is different than older Bosch 2.25 Hp that may require a larger fuse in the end. I also use the Bosch and I haven't experienced this. As Steve points out, several factors would contribute to this. Although maybe there's something in the circuitry of the newer Bosch routers that is contributing to this. What about temperature and air flow around the control box as well? How is your power source? Mine is shaky so I have a power conditioner in front of the computer, control box and router to condition the power.

SPH01
Posts: 91
Joined: Tue Nov 01, 2011 8:35 am
Location: Gavilan Hills, CA

Re: Fuses blowing in Control Box

Post by SPH01 »

I was under the impression that the newer Bosch routers had the "no power on AC failure" built it so you couldn't use the controller to start them.
Basically the power switch on the router MUST be in the off position before the AC power is plugged into the cord, prevents ouch I lost my finger.
This is likely to be a new federal standard before long and the circuits I have looked at, it's all built into the speedcontrol IC, no easy work around.
I would have no problem installing a slow-blow fuse. The intent of the slow-blow is for startup current rush not popping the fuse.
Steve

rungemach
Posts: 460
Joined: Mon Aug 02, 2010 8:24 am
Location: Sarasota, Florida

Re: Fuses blowing in Control Box

Post by rungemach »

I'm not sure a "one size fits all" approach to the fuses may be appropriate for a controller that can go from a Colt at 5.6 amps to the larger routers, that the HD is made to accommodate, at 12 amps. On the larger routers, the 10 amp fuse seems to be marginal, and may be Ok for light cuts. The machine is marketed as a HD (Heavy Duty) model. I think the assumption is that the machine should handle "normal heavy duty cutting" of wood that the router was made for. Trying to cut through the table or an aluminum clamp would not be considered normal for the router.

Since the fuse size is somewhat uncommon, its failure becomes an inconvenience that a quick trip to the hardware store can not resolve.
Joe has suggested keeping spares around, and that is a must. But what value? They are available in increments over and under 10 amps.

When using a Colt, there is plenty of headroom over the published amperage spec. If you assume the controller and steppers at 2 amps total, you will have around 20% headroom with a Colt. When using the larger routers, the fuse is 20% or so under the full load of the router, not considering the extra current drawn by the controller and stepper power supply. If the router has to go through the occasional knot, it will draw more current and should not take out a marginal fuse.

It would be good to see some recommendations from the factory on the appropriate size fuse for each class of router. The 10's seem a bit light for the large routers, and maybe a bit heavy for the Colt class. If the power supply for the steppers is separately protected, increasing the value of the main fuse should not put the other electronics at risk.

It is good to explore the other factors , like dirty power, local line voltage, etc. To me, the 600 lb gorilla in the room is 14 amps of rated load on a 10 amp fuse.

Post Reply