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lamestllama
15th Jun 2019, 11:13 PM
I have a Taiwanese 12 x 7 bandsaw sold through Hercus sometime in the 1990s. Today I finally got it working.

The saw has the normal starter on/off buttons and a contactor so I was surprised by what happens when the saw reaches the end of its cut.

As it reaches the end of its travel it pushes a toggle switch down which turns off the bandsaw. I would expect this to release the contactor in the same way as pressing the stop button but to my surprise toggling this switch back turns the bandsaw back on. I consider this dangerous. Has anybody else come across this weirdness in one of these saws?

KBs PensNmore
16th Jun 2019, 12:09 AM
Hi Eric, any chance of a pic of the switch and shut off mechanism please? If I remember rightly which possibly is wrong too, but the switch had 2 buttons one to start and one to stop, is this what you have?
Kryn

BaronJ
16th Jun 2019, 05:44 AM
Hi Eric, Kryn,

I would have thought that the thing would have been wired in a "No Volt" configuration, where in the absence of the mains supply the contactor drops out and isolates the machine so that it cannot start up without pushing the start button.

I assume that the toggle switch doesn't pop back up by itself in which case a normally closed push button may be better.

Michael G
16th Jun 2019, 09:14 AM
My saw has not got a contactor, but does have the toggle switch that is pushed down at the end of the cut. Occasionally, when I lift the saw I discover that has not gone all the way down and the saw restarts (Not often these days - I think I have the adjustment about right now). It is certainly something to be aware of.

If you have a contactor, wiring the toggle switch to cut the power to the coil would be an improvement.

Michael

eskimo
16th Jun 2019, 12:21 PM
assuming start switch is momentary it is wired wrong in my opinion.

should be a simple matter to correct.

lamestllama
16th Jun 2019, 12:24 PM
assuming start switch is momentary it is wired wrong in my opinion.

should be a simple matter to correct.

My thoughts exactly.

BaronJ
16th Jun 2019, 07:14 PM
Hi Guys,

A simple diagram for wiring a No Volt switch.

380034

Sorry its a bit dark, found it on the net ! "A" and "B" are part of the contactor. The push buttons are the red and green ones.

lamestllama
16th Jun 2019, 07:49 PM
I inspected the electricals on the saw this afternoon. The no volt setup is wired as you would expect but rather than put the auto cutoff switch in series with the off button of the no volt setup it is in the line to the motor after the no volt switch setup. Which is what gave me the very unpleasant discovery that I could start the saw without pressing the start button.

There has been a bit of cutting and shutting occurring in the past as there are some quite unorthodox connection methods employed. It is a fairly straightforward fix.

pipeclay
16th Jun 2019, 08:20 PM
Is this a dangerous thing outright in your opinion or only if you decide to play with the toggle while either setting a cut or holding your hand on the blade?

BaronJ
17th Jun 2019, 12:52 AM
Hi Guys,

Working with or on any machinery that can start up unexpectedly is a hazard !

pipeclay
17th Jun 2019, 08:47 AM
Hi Guys,

Working with or on any machinery that can start up unexpectedly is a hazard !
From my understanding of the original statement was that the machine did not start unexpectedly, the switch in question had to be intentionally reset.

eskimo
17th Jun 2019, 10:06 AM
My thoughts exactly.

I can have a look at it for you if you are not experienced in electrical
I can even bring that switch station over...lol

lamestllama
17th Jun 2019, 11:25 PM
I can have a look at it for you if you are not experienced in electrical
I can even bring that switch station over...lol

Eskimo,

Thanks for the offer but it is now fixed, I do still want that switch station though.

Eric

eskimo
18th Jun 2019, 10:14 AM
I do still want that switch station though.

Eric

I wont toss it

Michael G
18th Jun 2019, 07:53 PM
I go past Eric's place most evenings on the way home from work. Happy to relay if easier.

Michael

eskimo
18th Jun 2019, 09:09 PM
I go past Eric's place most evenings on the way home from work. Happy to relay if easier.

Michael

Eric?.

Michael G
18th Jun 2019, 09:22 PM
Sorry.
Member code name 'lamestllama'

Michael Michael G