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Dewalt DW618 noised motor and almost no power

19K views 33 replies 12 participants last post by  Stick486  
#1 ·
This weekend my Dw 618 started to make a different noise (sounding really nasty) and lost your power. I immediately turned off and open the cap to see if was anything broken or burned. It's seems everything is ok. I'd spin the center post (communicator?) It spun freely it didn't feel like it was grinding on anything. So I suspect about carbon brushes.

Are these brush motor heads bad? Is this may be the problem?

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I take some pictures and made a little video to help.

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Youtube video:
youtube.com/watch?v=_-CyXYR5Hxc
 
#4 ·
Hi Joel and welcome. Where the brush makes contact with the commutator doesn't look that good. It looks rough and it shouldn't be. The other main cause of noise is bearings so roll the shaft over quite a few times by hand and see if you can feel rough spots. If you do they need replacing.
 
#6 · (Edited)
Welcome to the forum Joel. Was this router mounted in a table when it started making noise ? If so make sure a small screw or something hasn't gotten inside . Not sure if that is possible but makes one wonder . Those brushes don't look great IMO
 
#9 ·
No. It doesn't.

Hi Joel and welcome. Where the brush makes contact with the commutator doesn't look that good. It looks rough and it shouldn't be. The other main cause of noise is bearings so roll the shaft over quite a few times by hand and see if you can feel rough spots. If you do they need replacing.
The bearings seems to be Ok. I roll it the by hand and dont feell nothing abnormal.

Today I realized that speed control isn't work either. Due the commutator issue the motor can rotate to your full rpm.
 
#11 ·
My motor did the same thing last week and the brushes looked the same way. I bought a Bosch motor to put in my table, and the DeWalt is off to the service center. Since mine is under a year old it will be free to repair/replace. I read somewhere that using the 618 in a table (which I do predominately) is not a good idea. Something about the top bearing? As with yours mine felt fine so I tried to continue and wound up with sparks flying everywhere and the motor speed fluctuating. If I get any answers from the service center I'll let you guys know!!
 
#14 ·
Of those who have had problems, who have it mounted in an enclosed cabinet with the dust collection below it? Just curious as my stance on the subject is that it is a bad idea.
 
#18 ·
It looks as if there was considerable arcing on the brushes. From my motor experience you may have an open winding on your armature. Usually on a small motor if you can't find a replacement at a decent price it's not worth the cost of having a repair shop do a rewind. Occasionally you can find a broken connection to the commutator and do a re-solder job. Out of several that I've worked on in my life time I've only been able to repair a couple. I just scrapped an electric chainsaw after trying and to do a repair and burning up 2 new sets of brushes. I couldn't buy replacement parts and it was only 2 years old. It looks like the cost of a new armature may be about 1/2 the cost of a new router.
I can't post a URL link since I don't have 10 posts but I have a good site on trouble shooting but here is part of the link.
ereplacementparts.com/article/968/Diagnosing_Electric_Power_Tools_101.html#decrease
 
#19 ·
When I built the box under the table for my router,I cut a hole in the bottom the router sticks thru so it is always breathing clean air. The shavings are sucked from around the router and out of the box. works like a charm.

Herb
 

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#21 ·
I agree, well thought out. The suction should not interfere with the air movement through the router that way. If the box was longer (hung down farther) and the intake was on one side of the router and the suction was on the other side then the air flow across the end of the router would tend to want to create a Venturi effect and create a vacuum inside the router.
 
#22 ·
I have read cases on other forums of the abrasion of the chips being sucked thru the motor have caused the insulation on the field coils to fail and short out the router over time. This is not my design, it was an engineer that came up with it. As you can see this design has an adjustable air opening in the side to adjust the air flow to the dust collector.

But, most commercially designed boxes have the suction air outlet located in the bottom and are fully enclosed ,so maybe this is overkill.

Herb
 
#27 ·
Maybe the adjustable air inlet is for different sized vacs/hoses. The boxes air inlet plus the gap around the bit should be equal in cross sectional area to the air outlet opening. Vac systems depend on enough air volume to keep particles suspended in the air stream. If the vac hose is fitted to the bottom of the box, at or near the router, and there is no air inlets in the box then the vac is competing 100% against the router's airflow and it is possible for chips to be drawn into the motor. You also have the heat generated at the cut being drawn back through the router added to the heat the router is already generating. All of this is a recipe for early mechanical failure. It's all part of the reason I like having my DC in the fence, although the DC built into some routers is also good for all the same reasons and will probably work better when making grooves as opposed to profiles.
 
#23 ·
Dropped mine off today. The first thing out of the gentlemen's mouth was, "did you have it in a table?". With some hesitation I said yes. He said that in 90% of these cases something fell into the motor and broke the mag ring. He also said based on the fluctuating speed that the magnetic control switch may have gone bad and they will check the mag ring. When I get it back and have more information I'll let you guys know. I'll be sure after I've got my router in hand and no money has been exchanged to get all the info I can from him about his feelings on mounting the router in a table. As for mine it will never see the underside of a table, I already received my Bosch 6118evs and will dedicate that to my table. So far with very little use the returns are great. I do have one question for any who has purchased just this motor. (It's the same as the 6117evs only with a short cord.) It came with two round head screws that seem to be holding the bearing around the collet in, are these just a shipping thing and should be removed, or are they actually holding in that bearing? It came with 4 pan head screws that I assume are for mounting a base but was worried that there may be some kind of ring that goes around the bearing to hold it in? I know this is a ridiculous question I'll get some pictures when I get to the job today to show you all what I'm talking about. Thanks in advance!!
 
#28 ·
There are some routers that trap the bottom bearing between the housing and a screw held cup or plate. The best way to find out is with a schematic for that router.
 
#29 ·
Yeah, I looked at them online last night. Their shown in the exploded diagrams. I wonder if backing them out and putting a drop of blue loctite on them is a good idea? Maybe I'll call Bosch. I just put one router in the shop, I'd like to have this one at least until I get that back. :)
 
#33 ·
Mine works under a router table for few times (max of 15) without dust collection, but last days I was using it most with plunge base. It didn't broken under table, my last use (during last 3 weekends) was all in plunge base.

When I opened it, I didn't see any broken item inside the cap, magnet ring seems to be fine, I don't know if "broken magnet" is broken in physical parts or just electrical broken. Before him break, I plugged it in 2 power cord extensions with about 23 feet (7m). This cord has appropriate gauge, the plugs and motor didn't seem to be hot.

Does bad bearings can be a cause of a underpowered motor?

I sent for Dewalt service last week, so i expect for the next days a answer about fixing costs.
 
#34 ·
Mine works under a router table for few times (max of 15) without dust collection, but last days I was using it most with plunge base. It didn't broken under table, my last use (during last 3 weekends) was all in plunge base.

When I opened it, I didn't see any broken item inside the cap, magnet ring seems to be fine, I don't know if "broken magnet" is broken in physical parts or just electrical broken. Before him break, I plugged it in 2 power cord extensions with about 23 feet (7m). This cord has appropriate gauge, the plugs and motor didn't seem to be hot.

Does bad bearings can be a cause of a underpowered motor?

I sent for Dewalt service last week, so i expect for the next days a answer about fixing costs.
yes...
 
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