Table Saw Wiring Upgrade challenge. 1

[xcmtb]

I am probably going to be ridiculed off this forum for my lack of EE technical knowledge, but I do beleive I have an interesting challenge:

I have a Skilsaw (model 3400) Table Saw. Before I was given the saw, the switch went bad and was replaced with a 20 cent light switch. I could just order a new switch from Skilsaw, but this would not fix the primary issue I have with this saw, the motor is "direct" wired to the plug-in cord. (There is no capictor/starter...) When the saw is turned on, it sounds like a hammer smashing a nail it starts up so fast, (and scares the hay out me everytime!). Quality saws have some kind of capacitor/starter system? that transitions the motor up to full speed.
So my question is how and what components do I need to make up this "starter system"
FYI, I talked to a Skilsaw service rep, and the "instant on" starting is normal -because this is just a cheap saw, (the new switch would not have any of this built in it).

Saw Info: Amperage 15.0, Max Motor HP 3.0, No load RPM 5000, Rating 120v. There are only two wires to the motor, if the motor plate data is needed, I can post it...

Thanks in advance! if anyones interested in helping me out.
-XCMTB

 

[pablo02]

First of all, hire a competent electrician to replace the "20 cent light switch" with the Skilsaw replacement switch -- this is a double insulated piece of equipment so there is no ground wire -- using this substitute switch has potential electrical shock hazards to you

as for starting, the motor is doing what it is supposed to, the use of a capacitor will not change anything -- look for other causes:

you might check this link, esp the tech note regarding checking the gear housing for cracks:

http://www.skil.com/NR/rdonlyres/em...yh43zkjw2ccblrllf4ppjkgjuqtfbie4ml3b/3400.pdf

also, check the owner's manual for lubrication requirements and causes of excessive vibration (also check for excessive wear in any pivot points for the saw motor/blade aseembly):

http://www.skil.com/NR/rdonlyres/em...zich6qt2metclxollfl6tykwrl56bb/01+3400-T4.pdf

rather than blame the motor, consider a good inspection, tightening, lubrication of the saw... if the motor is at fault, the easiest thing to do is to a) buy a new replacement motor from Skilsaw, or b) buy a new saw...

hope this helps...

 

[pablo02]

I should also point out that 1) this type of saw will probably make a lot of noise as it starts up -- something to get used to and be sure to wear hearing protection and 2) good safety practices dictate to never stand in front of the saw (blade) as it comes up to speed; that way, if it comes apart due to cracks or throwing off cabide tips, you aren't in the direct path of flying debris..

 

[peebee]

I agree completely.

1. Change the switch out for safety reasons previously noted.

2. The capacitor start circuits you're talking about have nothing to do with ramping up the motor speed, they are there to get a specific motor type to start. You most likely don't have a capacitor-start motor. You most likely have a "universal" motor (rather than a "squirrel-cage" motor). Universals are commonly used in small tools, vacuum cleaners, etc., because they're cheap, small, and ac/dc. But they are also really noisy. Nothing much you could do short of swapping out the motor.

 

[xcmtb]

Thanks!

I agree completely with the safety recommendations and I do plan to replace the switch with the correct service part.

The link to the housing bracket service bulletin is greatly appriciated. Thanks for effort to bring this to my attention, I'll check it out tonight.

I have to admit I am a bit disappointed that there is no way to make it start up smoother, but it seemed like a good idea...

-Jason

 

[rbulsara]

xcmtb:
You can always make the motor to start smoothly (with added cost of course), but you need to verify the type of motor first.

While it may be true that such motor will start with a big jolt but it should not sound like a hammer smashing a nail when it starts as you mentioned. If you are hearing/feeling multiple 'bangs' you do have a problem with the motor.

'Universal' motors have brushes and a commuter (copper strips on the rotor where carbon brushes sits). If not the motors has to be one of the following:

split phase : no cap required but may or may not have centrifulgal switch

or a capcitor run/start type. Could you please verify or have some one verify the type of motor you have? is there a nameplate on it?

You can always make the motor to start smoothly (with added cost of course), but you need to verify the type of motor first.

 

[pablo02]

You might look at this link: I have no idea if it would work on your motor (it is the universal type with brushes) -- use the speed control for starting, switch to full speed when ready to work... (I ordered one for my router..)

http://www.woodworkforums.ubeaut.com.au/showthread/t-3456.html

but first, do a thorough check up on the saw including all the linkages, etc...

 

[peebee]

Just a thought -- are you sure it's the motor making the noise on starting? Don't most table saws have brakes? Any chance it's the brake making all the noise?

Maybe you should just have the thing serviced.

 

[GusD]

xcmtb

Good advice on the safety aspects of saw use as well as
making sure that electrical components are right for the job.Electrocutions in the home run very high and the reason is because of the short cuts that we probably all take from time to time.Safety first for all of us.
If your motor has a centrifugal switch ,it could make a loud noise depending on the type used.You should also hear some noise from the switch when you stop the saw.It won't be as loud but you should hear it nevertheless.
The brake, if your saw has one,could give a pretty good snap depending on type used.I don't know if I would compare it to a "hammer hitting a nail" but like everything else, the sound it makes depends on the hear of the listener.

Good luck

GusD