Has qualtex inmproved on their bosch brushes?

Re: Has qualtex inmproved on their bosch brushes?

Do you use brush seater,it makes a better job and reduces whine.

Re: Has qualtex inmproved on their bosch brushes?

http://www.masterpart.co.uk/ItemDetails … ode=SE5504
When the old brushers are at the end you get arching which balackens and scars the armature then you use the seater sometimes called a com stick,after you fit the brush you hold the seater compound onto the com and rotate the armature,the compound rubs off cleaning up the com at the same time as helping the brush to sit snugly on the radius of the comm which ensures better contact and less likelyhood of sparkin/arching/.

Re: Has qualtex inmproved on their bosch brushes?

eastlmark wrote:

spimps wrote:
Do you use brush seater,it makes a better job and reduces whine.

WTH is brush seater?

ah, com stick, thats more what we know! Gave up on them years ago. IMO if the coms good they are not needed, if the coms bad they do not help at all. as for the Bosch’s have always used gen and never once had a call back or problem.

Re: Has qualtex inmproved on their bosch brushes?

have never cleaned coms but advise customer to keep away from heavy loads and use low spin speed for 10 washer to aid bedding in especially on the hoover p55 motor which seems to hate new brushes

Dave

Re: Has qualtex inmproved on their bosch brushes?

electrofix wrote:especially on the hoover p55 motor which seems to hate new brushes

Yes I’ve found that too with Hoover motors…..pain in the proverbial they can be! :rolls:

On the subject of comm bedding sticks, there is little or no point in cleaning a commutator expecting new brushes to bed in better or to reduce the excessive arcing.

The only purpose of bedding sticks is to remove the brush worn grooves on very elderly armatures. Or, more common on later armatures*, to try to remove the central groove caused by the metal tags scoring the comm.

Now on the specific issue of Bosch armatures the former problem doesn’t manifest ever itself, whereas the latter central groove problem is very commonplace. The use of a bedding stick is paramount in these circumstances. Likewise a full strip-down of the motor to clear away the years of carbon dust is necessary especially when the dial on your megger shows any sign of insulation problems.

Having gone to all that trouble you will still find that new brushes will arc and arc badly especially these cheap pattern brushes. And the simple reason for that is all too apparent in that whilst they are chamfered at a reasonable angle to the commutator are nonetheless a flat fit onto a rounded surface. The proverbial square peg in a round hole and no getting away from that fact.

And filing the contact surface to attempt a better fit is not an option either. That would involve precision engineering tooling in Ross Brawn’s workshops to get right. Leaving the only option toward slow speed ‘bedding in’ techniques and that doesn’t involve a bedding stick!

For those that will only fit pattern brushes to Bosch motors I would ask you to try a little experiment, if you are up for it that is?……………

……….to do this though will involve investing in one pair of genuine (154740) motor brushes though. 😉

Then the next time you get a motor that’s arcing like a chinese firecracker just take out your make of pattern brushes and replace them instead for the genuine full monty article. OK so it will take up some of your valuable time I know but you may be surprised at the result?

It’s not a magic bullet answer and you’ll notice that they too may arc a little but far far less. An yet they too, coincidentally, are flat and not round to the armature. They too require a little bedding in but of little consequence overall and you certainly won’t get a recall 3 weeks later to find the armature has burnt out.

Hands up those that have fitted pattern brushes then found the motors burnt out some short while later?………….spooky that ‘ain’t it?….ever wondered why?……..blamed it on a dodgy motor I expect?….nothing to do with you fitting pattern brushes was it?….Oh no, not guilty M’lud! 😈

Seriously guys…..try it…..pattern brushes are OK for the most part at least, don’t get me wrong, I fit them all the time…(not on BSH stuff mind you). Try fitting the genuine whenever you get a Bosch motor that you’re worried about excessive arcing.

Sure they cost 4 or 5 times more but all good things cost more, quality comes at a price and reliability follows suit. 8)

(*Modern armatures usually have laminated brush gear. Laminated brushes have a lubricant quality that doesn’t readily wear brush grooves in the armature at all!)

Re: Has qualtex inmproved on their bosch brushes?

when I was a college many yeaes ago a we were taught “commutation is that which is occuring in tha armature during the short circuiting period of the brushes” in other words the direction of the magnetic field is changed. excess sparking could therefore be inbalance in armature magnetic flux i.e. bu*****d armature or bad contact from brush to commutator. we were also taught that higher resistance brushes help to “dampen” poor commutation.
I sometimes find motor arcing on bosch but I find that cleaning the com with a rag dampened with WD40 helps as it removes residue between segments also you must be sure that the brush is well down so that the spring pushes the brush firmly ont the com and is past the tight section of the holder.

so theres my two penny worth!!!!!!!!!!!!!

wilf

Re: Has qualtex inmproved on their bosch brushes?

Probably habit with me,was using com sticks on motors late 60’s Hoover etc and Lux vac motors and still do.
Use gen and pattern brushes,always put a small chamfer on the edge in case there is a slight groove in the comm although they don’t seem to wear like they did.