On Thu, 27 Apr 2006 13:24:41 GMT, "Toller" wrote:
"LRod" wrote in message
.. .
On Thu, 27 Apr 2006 07:55:21 GMT, "Toller" wrote:
"Steve W" wrote in message
.com...
I have a Delta hybrid TS (36-715) and just wired it for 240v. Now the
thing starts up so fast it makes me worry about belt wear.
Anyway, in the manual it says to make sure I have a 240v rated switch.
The switch has no rating marked on it so how can I find out if it is ok?
A 240v switch opens both wires rather than just one. All my tools say if
it
is 240v in the manual; if yours warns you to be sure you have a 240v
switch,
you probably don't.
If it doesn't say on the switch, you can tell by measuring (after the
switch, with the switch on off) the voltage from each wire to ground. If
either is 120v, then it is a 120v switch.
That explains why you need a 240v switch. While the tool works fine
either
way; a 120v switch leaves wire energized that you would expect to be dead.
Please don't give electrical advice.
There is a huge difference between whether a switch is physically
capable of switching 240V (DPST), and whether the contacts (regardless
of switch configuration) are rated at 240V.
Even a SPST switch is technically capable of switching a 240V device
on and off--if any break occurs in the circuit (that is, either leg)
the motor will not run. That is what you alluded to. There has been a
fair amount of debate here as to whether that's a good idea or not.
However, if the switch contacts are only rated for 125V service it's
not a good idea to employ the switch for 240V use irrespective of
whether it's a SPST or DPST.
Now, to answer the OP's question, I would be very surprised if there
wasn't any voltage rating marked on the switch. I would have thought
that a requirement. In any event, I believe one of the other poster's
answer is probably a good idea--contact Delta.
You are FOS.
Really? Let's review:
A SPST is not a 240v switch in this country, even if it is rated for 240v.
Huh? In this country (which country is that, by the way? Do you even
know where I live?) I'm pretty sure I can switch 240V with a SPST
switch (assuming it's rated for 240V). The test might be "does the
motor work when I switch one leg of the two pole, single phase
electrical service" which would absolutely not be true. Of course I
could also be switching a 240V plate supply in a vacuum tube circuit,
in which case a SPST switch is all I'd ever need.
If you look at a SPST circuit breaker it says "120/240vac". By your
reasoning you could use one to protect a 240v circuit. It would work,
wouldn't it.
Huh? Who said anything about circuit breakers? I certainly didn't.
Well except that the circuit would still be energized between
the unswitch hot and the switch. There is no debate over it; well, except
between you and another person FOS.
In any circuit, if it is interrupted, it will no longer work. That's
dirt simple, fundamental electronics. You seem unable to even grasp
that.
A DPST is a 240v switch;
Really? That's the first I've ever heard that. That will certainly
save UL and a whole lot of other people a bunch of work testing switch
dilectrics for voltage capacity.
...find one on a woodworking machine that isn't rated
for 240v. There is no reason to read the switch, except to see if it opens
both wires.
Huh? So you're saying that when you want to change a dual voltage
motor from 120V to 240V and the owner's manual says "make sure you
have a 240v rated switch," your solution is to just fire it up and go.
You don't feel any need to check to see if the switch is rated at
240V. Worse, you somehow feel the need to propagate that
irresponsibility to innocent users who haven't as yet had a chance to
witness your electrical incompetency over a period of time.
In fact, a motor switch will handle a larger motor on 240v than on 120v;
didn't you know that?
Huh? What does that have to do with the OP's question?
In short, open both wires good, open one wire bad.
But not illegal. Intuitively (and solely from the safety standpoint),
I would prefer to switch both legs, but I don't believe it's necessary
(and it isn't necessary from an electrical standpoint).
So, in the final analysis, in regard to your statement:
You are FOS.
I can only point out the obvious and say PKB.
Don't you get tired of embarrassing yourself? Stay out of electrical
discussions and you will reduce your vulnerability 100 fold. You
haven't a clue as to what your're talking about--just a few buzz words
you throw together like monkeys at typewriters.
--
LRod
Master Woodbutcher and seasoned termite
Shamelessly whoring my website since 1999
http://www.woodbutcher.net
Proud participant of rec.woodworking since February, 1997
email addy de-spam-ified due to 1,000 spams per month.
If you can't figure out how to use it, I probably wouldn't
care to correspond with you anyway.