Does anyone why power tools have small capacitors?

[barcaloco]

i noticed while trying to repair a rotary hammer there's a small circuit board linked in with the switch with 2 5v capacitors (i think they're capacitors).

are these used to give the motor a boost on starting?

 

[telectrix]

is it something to do with speed control ( light trigger pressure gives a slow speed) or they could well be suppressors to stop TV and radio interference.

 

[Des 56]

Capacitors will reduce sparking between the brushes and the commutator ,the motors will operate without them,but the brushes will wear quicker
And as tel said,it reduces radio interference

 

[Darkwood]

There called flux capacitors ... when your drill speed hits 88mph you are zapped into the future and a hole appears where once there wasn't a hole.
That or as Telectrix has suggested, but usually found in alot of hand held motor devices like hairdryers etc and as far as im aware as already mentioned they reduce radio interference so you dont get a wiggly line migrating across your television or frequency crackling on the radio.

 

[yellowvanman]

Capacitors are also used to make the motor rotate for single phase machines.

 

[telectrix]

There called flux capacitors ... when your drill speed hits 88mph you are zapped into the future and a hole appears where once there wasn't a hole.well, that lets me, tony,des,malcolm, and a few other members, out, coz. we're all stuck in a time warp in the past, where cable was cable ( 7/029 ), sparks were sparks, apprentices spoke when they were asked, and a 5 week wonder was the tally man ( septic knuckles ), who caught you one week in five if he got lucky.

 

[mackers]

because big ones wouldnt fit in!!!!!!sorry couldnt resist lol

 

[Des 56]

Anybody know the techno on these Flux capacitors ?
When she lets me out on the booze,it would be so handy to zip back an hour or two,saves all the nagging when I eventually fall through the front door

 

[Knobhead]

Capacitors are also used to make the motor rotate for single phase machines.

Motors in hand tools are universal motors. The capacitors are for supresion, otherwise they would be much larger.

 

[Knobhead]

Anybody know the techno on these Flux capacitors ?
When she lets me out on the booze,it would be so handy to zip back an hour or two,saves all the nagging when I eventually fall through the front door

Traveling back in time will remove all the booze from your system! What's the good of that?

 

[barcaloco]

thanks, so the motor should run even if they had blown, because right now it turns a bit then hums, thought it might have been something to do with the capacitors

 

[Kenny.]

If its a series motor that rotates then stops (in the same place every time) them its likley to be an open circuit in one of the armature coils.

 

[Des 56]

Ok Barcaloco,this tool is giving you jip,your last thread,you said, "it must be the brushes"

Have you tried a continuity test of the commutator?
Remove the brushes and test between one copper segment and its end on the opposite side of the commutator for continuity and also to nearby ends to check for short circuits ,if any of these are open circuit or short circuit, it will affect the machines ability to rotate
If you find shorts you can use a hacksaw blade to undercut the mica and get them seperate again.clean the commutator copper
Have you also tried gently pushing on the brushes with a screwdriver to eliminate lack of spring pressure

Finally if all this fails, then bin it

 

[Guitarist]

Ok Barcaloco,this tool is giving you jip,your last thread,you said, "it must be the brushes"

Have you tried a continuity test of the commutator?
Remove the brushes and test between one copper segment and its end on the opposite side of the commutator for continuity and also to nearby ends to check for short circuits ,if any of these are open circuit or short circuit, it will affect the machines ability to rotate
If you find shorts you can use a hacksaw blade to undercut the mica and get them seperate again.clean the commutator copper
Have you also tried gently pushing on the brushes with a screwdriver to eliminate lack of spring pressure

Finally if all this fails, then bin it

No no, you mustn't bin it.... You must take it to your local recycling centre where it will be turned into copper nik-naks and watering cans. The fact that you burn a gallon of fuel and exude toxic fumes to get there is by-the-bye...

 

[barcaloco]

Ok Barcaloco,this tool is giving you jip,your last thread,you said, "it must be the brushes"

Have you tried a continuity test of the commutator?
Remove the brushes and test between one copper segment and its end on the opposite side of the commutator for continuity and also to nearby ends to check for short circuits ,if any of these are open circuit or short circuit, it will affect the machines ability to rotate
If you find shorts you can use a hacksaw blade to undercut the mica and get them seperate again.clean the commutator copper
Have you also tried gently pushing on the brushes with a screwdriver to eliminate lack of spring pressure

Finally if all this fails, then bin it

i haven't tested the commutator itself no, i will do that, i'll take the commutator out and give it a clean also

you're right if that fails it's getting binned, as much as i'd like to revive it. it's more about finding out exactly what the problem is because i've seen this problem before a few times and wondered what it was

thanks for the help chief