Farmall Cub

I got a Red-Star/Delta 40-A Multiplex/Radial Arm Saw, that needed a new capacitor...the guy that had it said he put a new plug on the end of the cord to go from 110V to 220V, and he reconfigured the jumpers per the diagram on the motor and when he plugged it in it blew the capacitor. Prior to that, it ran fine on 110V.
After spending a few minutes with the guys at the electric supply store, I found out that the capacitor he blew up was voltage specific for 110V.
New one was only $7 !
Purchased it, installed it, and reconfigured the jumpers on the board as shown for 110V.
Plugged it in, turned it on, started like a champ and ran for about 15 seconds and blew the new capacitor! ...stinky smoke for sure!
I unplugged it and will need to figure out the next step.
This is a very rugged and over-engineered woodworking product from 1950 that I purchased primarily for the 1-1/2HP motor power and ripping capacity.
Any ideas on what I should do next for troubleshooting would be very much appreciated.
marion

Marion:

Stupid question...

I got a Red-Star/Delta 40-A Multiplex/Radial Arm Saw, that needed a new capacitor...the guy that had it said he put a new plug on the end of the cord to go from 110V to 220V, and he reconfigured the jumpers per the diagram on the motor and when he plugged it in it blew the capacitor.

While you were reconfiguring it did you change the plug back to 110 ?

Yes...you silly boy !
I put on a brand new industrial 110V plug, and wired it correctly.

I told you it was a stoopid question

You got a model # on that motor? That way we can find a schematic and troubleshoot from there.

Normally I am not great at electrical but I have been rewiring the motors in my shop for years. So far i haven't electrocuted myself --- yet

It's a Red Star Products Cleveland Ohio.

MJ-4751 1 1/2 HP 60CYCLES 1 PHASE 115/230VOLT

Original Capacitor (CONDENSER) was a SPRAGUE #216-240 MFD

The motor housing is square.

Marion:

That is one really cool radial I like the older ones as they were so much better built and definitely more robust. I have an early 70's B&D model that I really like. Anyways, I searched the net for info on your radial and found the original Delta-MultiplexInstruction Manual. Spent a bit of time going through it. Manufacturer's sure could learn a thing or two about manuals by researching their own archives. Nice manual I am assuming you already have the manual.

I haven't seen the schematic though .. doesn't seem to be in the manual.

It could be as simple as a defective replacement capacitor. Double check your connections if you haven't already done so. Some of these electrolytic capacitors sit on shelves for a long time and they will dry out. You could also consider a higher voltage rating.

On the inside of the handle that you use to push and pull the saw back and forth there is a diagram. I drew it up on a sheet of paper for reference.



Here is a list of info regarding the condenser/capacitor units.

Of course, the new ones I bought were made in CHINA....ugh.



Are you saying Bigdog, that I can use the 220V capacitor with 110V power supply and see what happens?

http://hvac-talk.com/vbb/showthread.php?t=464362

Interesting read. Couple of possibilities cited.

Here is a picture of the circuit board and related motor components I'm dealing with.

The two spade connectors were not marked...I just assumed they were for the capacitor, since ALL the other wires were clearly marked for location.

Is it possible I just got 'unlucky' and reversed the leads where they attach to the capacitor? The capacitor lugs are not marked for polarity.

I didn't think it would have polarity?? ...doesn't the hot wire just feed in one lug...kinda store up some and then come out the other?

marion

Marion - yes you can use the higher voltage capacitor. The voltage ratings on the capacitor are max operating voltage. What is important is the size (in MFD) of the capacitor.

Thanks Bigdog.
I will recheck all my connections again and then install the 220V capacitor and see what happens when I light it up.
I am in the hunt for a ripping and crosscut blade for it as well.
I've never owned a RADIAL ARM SAW before, and if I am reading correctly, it takes DIFFERENT blades than the type used on a traditional table saw?
The primary use I got it for was so I could make my own infeed/outfeed table that will allow me to rip 8ft X 4ft sheet goods to 2ft wide SOLO.
The 2ft of table on the operator side will slide and fold down when not needed.
I will probably just leave it set up that way and perform all my crosscuts on the tablesaw...we'll see. The radial makes compound crosscuts, but I can't see going to all that trouble setting up to cut crown mouldings I can cut up faster on my miter saw.

Marion:

What you need is a good blade with a negative hook which will reduce the chances of the blade grabbing the work and either trying to eat it or whipping it back at you. You definitely do not want to get slapped by a radial.

Buy the best blade that you can afford, never buy cheap blades. Even though I never buy cheap blades for my table saws, chop/miter saws or my radials there still is the chance for injury (been there done that) but with a high end blade the chances are greatly reduced. Freud are about the best blades on the market with CMT a close second - probably tied with Amana. A real good cross cut blade(thin kerf is nice) is what you will be wanting as that should be the primary job for your radial which is what a radial excels at. Yup, it certainly can rip and a whole lot of other stuff, but it can be a bear to set up and of course you do not have the clearance for those types of chores that you would have with a table saw.

I really like Freud blades. My radial has a 10" 64 tooth ATB blade that I have been running for a few years now and I am very happy with it. Yours is a 12" so... this may be what you might be interested in and it is quite affordable.

12" Coated Thin Kerf Sliding Compound Miter Saw Blade

PART#: LU91R012
COST: $79.99

72 ATB tooth, -5° hook, 0.090" kerf, 1" arbor.
Provides a fine finish cut for sliding miter saws and radial arm saws. Thin kerf blade requires less horse power to produce good results. Perma-Shield coating guarantees less working friction and less resin adhesion while preventing the development of rust.

Nice blade.

If you are interested in industrial such as carpentry/structural work then a heavier crosscut is called for. Thin kerf is ideal for cabinet/furniture makers.

No water what brand you choose make sure it is the designed for radial/chop/miter or sliding miter saws. The negative hook is a huge consideration when using a blade on a radial.

I have no idea on the wiring for this motor but I am curious as to the wiring of the relay or contactor. Is this the start relay?
The start capacitor will blow if the start relay or switch does not disconnect in a few seconds. Much longer and boom! I expect the starting switch is not disconnecting. Starting capacitors have no polarity but do have a high power factor or effective resitance which causes heat build up inside the case. A higher voltage capacitor will not hurt but will not help either. You can also just check the relay contacts to make sure they are free and movable. Tracing and posting the actual wiring would also help, hard to tell from the photo. No matter how many times I remove my glasses, I still cannot make out the wiring on the relay. I assume there is no centrifugal switch but the starter is switched by that relay, voltage or current driven but I assume voltage from the starter windings. There is a wire that is either burned or has a strip of black tape that lookes like it was soldered recently, is it shorting onto the screw end under it? Eitherway, something is either shorted from bad insulation and movement or the relay is stuck. Not much in a capacitor start motor, fairly simple.

Chinese component? Have lots of them, no issues in general.

This is the greatest how-to place for sure!
Landreo,
Thanks for the post!
Prior to starting the saw, I did look everything over to check for loose connections, frayed wire and scuffed up insulation. There is one place in the power cord outer sheathing scraped off, but it did not cut any of the insulation off the 3 wires inside.
I did wiggle that relay toggle and it did not bind at all.
The recent solder joint is where I put the tagged wire back on where it was before the guy took it all apart to have the motor tested.
The guy I got it from said he had the motor tested and that it was not bad.
He was having trouble finding a capacitor for it, and in the meantime, found a running(on 220V already) Dewalt radial for his shop and installed that.
I had the cover off, exposing the relay board as shown in the picture. When I threw the switch, I did hear and see the relay close. I did not look to see if it opened back up however. Then, when the capacitor blew, my focus was on getting it unplugged! Luckily, I was NOT in line with the end of the cap or I would have gotten blasted for sure.
You seem to have the real knowlrdge I lack in this situation.
A novice such as myself may do more damage poking around and trying this and that...so,
what can you offer for troubleshooting steps that will not hurt the motor further?
There is no blade mounted on the shaft yet either, but I didn't think that would matter at all as far as whether the motor runs properly or not.
Can I remove the blown capacitor, jump the two leads and test for the relay to close and open?
I guess I need to know exactly how this thing should act when turned on also.
From what you posted, am I correct in the following?:
TURN ON THE POWER-relay closes, energizes capacitor and starts motor?
THEN-somehow the relay times out and opens, disconnecting the capacitor from the power source, and the motor runs on current that does not go thru the cap?
I have an old drill press with a 1/4HP 1725?rpm motor on it with a cap housing on it...I can tell by how it starts up it has a centrifugal start/run winding switch?
It starts with two distinct sounds and a 'click' when the run windings kick in.
Do you think the radial saw motor has this type of setup as well?
When it powered up, it did seem to be running at high rpm (3450), like I'm used to with my 10" table saw.
Looking forward to your reply ...I really want to make some sawdust with this thing someday