Is a starter necessary?

[Bi11Hudson]

@Bi11Hudson . Bill - If the motor current is going through the pressure switch, and it sticks on start-up, would the kit keep going until the pressure safety valve lets go, and even then, keep going? Of course,it may be that the pressure switch kit has thru-line contacts rated for the motor, or operates some other internal stuff - I don't know.

I only mention it because a pressure switch I have here does not have the kind of contacts common for a motor relay, small little contacts, and is wired in a 24V circuit in series with the starter coil.

This also brings about the point that in big machinery, it is common to have a little 24V power supply transformer, and 24V relay coils, so that all the push-buttons, starts, stops, E-stops, whatever anyone might touch, and mounted externally, are operated with only fused a low voltage 24V on them.

Maybe this is more of an issue in UK, where the ring main is 240V 32A, so maybe not what one wants on and around over a machine. I always specified low voltage external kit for starting and stopping the big stuff. We exclude here the exotic stuff, like "intrinsically safe", for hazard area mining kit, which gets rather special.

That's affirmative, my compressor originally came from Sear's. Both the compressor and the (ASME) tank are "DeVilbis", the rest of the stuff is Craftsman.(Sear's) The contacts in the pressure switch are much too small to handle a 5HP startup, especially under load such as the compressor. Even with an unloader. . . That was my primary reasoning for adding the magnetic controller in the first place.

I had acquired it as junk and thought to myself "Now where would it be most useful?" I didn't have a table saw at the time or it might have ended up there. But in the long haul, the compressor would be the best place to use it. I installed it the first time the contacts failed. And converted the motor to 240 volts at the same time. Looking to reduce the line current.

And, to your question, the answer is YES, if the contacts welded I would be in deep do-do. The only "safety" on such machines is the pressure relief valve. I've never had the dubious experience of a duplex failure but thinking about it is frightening. And that on a good day. It could very well have happened. There is no indicator to note failure of the (purely mechanical) valve. It could fail and not be noticed for months.

You mentioned a low voltage magnetic controller for some of your equipment. Such is not the norm in the States with 120 volt supply. Most of our equipment, at the hobbyist level, is direct powered. The only machine I have that came with a magnetic controller is a (commercial??) planer. And the controls may well have been installed by the previous owner.

Outside of "industrial" installations and air conditioners, I haven't seen magnetic/low voltage controllers in "consumer" related products. It may well be the use of 240 volts supply(mains?) VS 120 volts supply. I'm not impressed with it, but that's the way it is. Most likely because it's cheaper and most manufacturers are looking at the "least cost" way of doing things.

Sorry, I could preach for hours on the safety VS cost of devices. There's no challenging the "Follow The Money" mind-set.

.

 

[Ulma Doctor]

i always liked footswitches
lift your foot to stop, push the pedal to start

 

[projectnut]

I like your Sheldon lathe Projectnut!!
How come the chip pan is so clean?

I haven't been able to spend much time this summer working in the shop. I generally clean the floor and the machines when I'm through for the day so the dogs don't track around swarf or get some stuck in their paws. They've been clean and waiting to be used for quite a while now. The wood working machines on the other hand are being well used. I'm not sure if I'm making any progress, but I've had to empty the dust collector twice this summer. The 10 gallon shop vacuum also gets emptied on a weekly basis.

To tell the truth I haven't used hardly any of the metal working machines in about 6 weeks. I started pressure washing the house and deck which has lead to repairs on the decking and benches. It's a bit frustrating trying to piece in new parts when the originals are over 30 years old and there isn't a straight board in the bunch. I was originally going to replace all the decking and the benches, but treated deck boards are all but impossible to find, and dimensional lumber isn't much easier. For this year the repairs will have to do.

Yard cleanup may be another daunting task this year that keeps me out of the shop. Late next month I'm supposed to get some more replacement parts. I'm not sure how mobile I'll be when the leaves start flying. They tell me "you'll be as good as the 6 million dollar man when we're finished". I certainly hope so. Looking at today's prices I think Lee Majors got a hell of a deal. I'm looking forward to being faster and stronger, but I'm not holding my breath. For being "retired" I certainly am not bored for lack of things to do. I start my day between 5:00 AM and 6:00AM and don't get back to bed until 10:00 PM or 11:00 PM. I keep telling myself "it's because I have so many things to do". In reality it might be because I don't move as fast as I did 20 years ago.

 

[Bi11Hudson]

i always liked footswitches
lift your foot to stop, push the pedal to start

A foot switch would be a very nice addition, within limits. I have a few "industrial" switches, but I personally wouldn't want one on any of my machines. The only place I have one is on the "variac" used with a resistance soldering stand. If you do opt to use one, be sure to use a guarded version. A dropped scrap could cause a serious problem.

.

 

[7milesup]

A foot switch on a tablesaw would be a no go in my opinion. Balance is critical and one is working with pieces of different sizes of stock. When you run a sheet through you are moving at least 4 feet, usually closer to 8 feet to get the stock through. I don't see a foot switch working at all.

 

[DavidR8]

I have a foot switch on my drill press but I would not want one for my saw.
I can see where the idea has merit, in practice I think it would be a bit sketchy.


Sent from my iPhone using Tapatalk

 

[Ulma Doctor]

A foot switch would be a very nice addition, within limits. I have a few "industrial" switches, but I personally wouldn't want one on any of my machines. The only place I have one is on the "variac" used with a resistance soldering stand. If you do opt to use one, be sure to use a guarded version. A dropped scrap could cause a serious problem.

.

i use these kind

 

[graham-xrf]

@projectnut : Oh yeah - I get so distracted just looking the stuff in your lovely shop!
Thanks for the pics.

 

[hman]

Thanks, I might do a bit of engineering to see if I can do something similar.

Here's a possibility for you. It's a design I came up with in 2009. Rick Sparber (an HM member and good friend) was kind enough to add to his website. Hope it's of some help to you!

https://rick.sparber.org/ssw.pdf

 

[Bi11Hudson]

A beautiful design. I have seen several Rick Sparber spots, nice work all.

What I would comment on here is the particular switch used and its' limitations. First of all, that design switch is available in two pole for use on 240 Volts. In the UK and other 240 volt line countries however, a two pole switch isn't usually necessary. A phase to neutral connection is the norm.

Now, the down side to my remarks. The contacts in any "light" switch are not rated for motor use any larger than a pedestal fan. A "Dremel" is fine, a drill press isn't. A lathe or table saw is out of the question, don't even consider it.

.