Startrite TA165 advice

[nwood]

Hi all,

Hopefully this is the correct forum for this, apologies if not, I've been reading these boards for a while but this is my first post!

Anyway, I recently purchased a Startrite TA165 saw but the wiring is a bit of a mess! On the front of the saw is a Danfoss C10 contactor but none of the wires are connected, there is a four core cable coming into the box which should go to the mains and there is a three core cable coming from the motor. I've had a look and the plate on the motor says that it is a Gryphon single-phase motor rated at 7.8A and the saw was sold as single phase so all good so far. I'm a bit confused as to where the wires to motor and the wires from the mains cable should go (I'll probably swap the mains lead for a three core one), does anyone have any idea as the contactor doesn't seem to match the description/images in the manual that I downloaded for the saw from Alt saws and I can't find any info on google?

Also when I collected the saw, the seller explained that the wiring was a bit of a mess but the saw did work, he demonstrated this by putting a 13amp plug directly onto the motor and switching it on and the saw seemed fine. With this in mind, do I even need the old Danfoss contactor or could I just fit a suitable NVR switch?

Also just to keep everything in one thread, has anyone fitted a 250mm blade to this saw rather than the harder to get 9" blades? It looks like it would fit with a bit of adjustment of the riving knife.

Thanks,

Nick

 

[Fitzroy]

Issue with switched on saws is starting current, it can be very high 30amps easy, in s simple switch this whole current is going through the contacts just under your finger, which I would find pretty scary! Many power tool switches use a lighter relay switch to close the main contacts so the switch you push only sees a tiny current. Directly wiring the motor to a regular plug will use the switch in the socket as the contactor which sounds a terrible/scary idea.

 

[nwood]

Hi Fitzroy,

Thanks for the reply, that makes sense. With that in mind I guess I really need to retain the contactor and find out how to correctly wire it up, it must have been working at some point as the saw has always been single phase and the reason for the messed up wiring is that the saw originally had a key lock switch (it came from a school) and the key has long since been lost.

Thanks,

Nick

 

[nwood]

Hi All,

I've added some pictures which will hopefully show the type of contactor and the current state of the wiring. The wire from motor enters the box near the top and is the three core wire, the mains wire enters near the bottom and is four core for some reason. Any help greatly appreciated.

Nick

 

[Fitzroy]

Nick,

It's hard to explain how this works without having a good dig about, i'll give you some clues and see if it helps. A typical contactor circuit diagram is below, in your case the supply for the appliance and the supply for the coil are the same supply. The machine supply ON switch energises the coil, a switch in the contactor then engages and provides a supply to the coil when you let go of the start switch. The coil holds the contacts closed for the motor supply. If any of the OFF switches are pressed then the supply to the coil is removed, the coil de-energises and the contacts to the motor open. I would expect the key switch is in the main live supply arm to the coil, put it in the circuit instead of one of the stop switches. Also if you ever loose voltage then the coil deenergises and all switching reverts to safe, requiring user input to restart not just a restoration of power feed, this is the no-volt-release part of the switch.

I think the manual is actually also correct and that your contactor and switch are original, i assume you have the cover for the contactor with the switch buttons in it? Page 5 shows a representation of the contactor. The pointer is actually the overload release (you can see this in the bottom right corner of your image next to terminal 14) in a 3 phase connection any one of the phases will allow an overload detection, hence one of the phases flows through the "pointer" but in a single phase machine it's different hence the handbook shows L1 flowing through the "pointer" before this phase is returned via a jumper to the next contacts before flowing across to the motor supply. In your photo it looks like the contactor is housed in another unit to enable connection to this overload protection. The metal strip from 14 to 13 is "i think" the jumper in the diagram.

I personally like to keep machinery original and if your contactor and original switch work then why change them, although based on ebay you could sell the C10 for £50! If you are thinking of a new switch unit then you are going to have to take all the wiring apart anyhow. I'd pull the contactor out of the unit and on to the kitchen table, working out where the key switch tied in etc, then build it up based on the circuit above. The great thing is you can get the coil and switches working without having the motor attached, then when every thing clicks and whirs like you expect connect on the big spinny dangerous bit.

Cheers

Fitz.

PS. Apologies if any of that is teaching granny to suck eggs.

 

[nwood]

Hi Fitz,

I would prefer to keep the saw original if possible and I do have the cover for the contactor with the stop and start buttons on it. However, it's pretty tempting to just get a new DOL starter which will presumably come with wiring instructions!!

From reading the side of the contactor, the startrite manual, your useful information and endless google searches, it does look like the mains should go to terminals 1 & 3 and the motor should connect to 2 & 4. The bits I am more unsure about are the metal strip (it's only connected at one end but with the curved edges doesn't seem broken) and the earth wiring in general.

Thanks again for your help, really appreciate it.

 

[flh801978]

The metal strip is your start switch which is pushed by the green start button
Your stop button presses onto the red button below on the overload

Ian