Member postings for Gareth Owen 2

Just to update if anyone needs the info I have had a response from the manufacturers.

Hi Gareth,

The T20b-1 were dedicated 3-pole ON/OFF switches, they were not true cam switches as they were only limited to this single function, refer to the attached catalog extract.

The T20B-1 switches are obsolete long years ago. Today these are represented by the ‘P’ line of switches. so you have to upgrade the entire switch with P series cam switches.

For example, if do you have T20-1/EA/SVB then you have to go with PN # P1-32/EA/SVB covers all of the old ratings and is the closest replacement however the pad-lockable handle and mounting hole pattern is different. below are the dimensions of the current P1-32/EA/SVB for comparison.

Thanks Clive it just goes to show you that we never know the abuse suffered by the machines we buy. There must be thousands of years of hard won experience on this forum. It really is an eye opener. I ambled on here and posed a seemingly innocuous question and people have taken the time to respond with some great advice. I wish that investment site had done the same for me when they all recommended Bitcoin haha

Having just re read my earlier post regarding calling a professional it may appear that I am am being rude. I certainly didn’t mean it that way.
I went down to a local engineering workshop and asked if they knew anyone. They did and I am in contact. He even said he worked for Colchester/ Harrison and probably has a spare switch in his spares. Looks like I’ve lucked out.
Thinking about it it wouldn’t be a bad idea to have a once over inspection just to make sure it’s safe anyway. Insulation does degrade... and those sudden bangs make you realise how sudden and powerful electricity is.

and Nigel... are you vying for the most comprehensive reply to a post? Wonderful info and thanks very much for posting. Like I say these posts stay up forever and someone may glean some knowledge like I have.
thanks

Just to let all you kind posters that I have contacted a professional!

I will update this post just in case it happens to any one else. Seemingly it could involve the higher voltages present in the switching on early Harrison’s of 415v. Hope I said that right!
anyway thanks

It didn’t work

Thanks Andrew

No problems 40+ years so far!!
At least if I sort it out then we will all know about flash bangs.

I will definitely not let this be another unresolved thread by a newbie

Thanks for the reply emgee. I actually had a hairdryer in there yesterday just to confirm or repudiate my ONE theory and hence why I have come here .

Thanks Dave

that was possibly the most comprehensive post I’ve ever read. Really appreciate it.
I suppose nothing lasts for ever and your explanation makes a lot of sense.
there is no way I would even look at the inside of the cabinet with the power connected and without the main board trip off.

I will try and source a new old stock moeller T20b-1

or get an electrician to sort it out with a newer type unless someone knows of a modern direct replacement

Once agian thanks a lot

Thanks for the welcome Thor and Chris. Never doubted that a model engineering forum would be welcoming.
If there happened to be a potential “ life saver” that lived in the York / Selby area I would certainly welcome some advice. If this isn’t the case does anyone know of a machine electrician in this neck of the woods?

My blood pressure isn’t faring well having to touch the lathe with the back of my hand just to make sure ... not that it would help with 415v I suppose

i am generally a very prudent person!

Hi all

Ive had my Harrison M300 for about 15 years. I’ve always run it from a Tanswave static converter. I bought myself a lovely Transwave Rotary converter and it ran for a while fine. Then there was a calamitous bang and then another. Couldn’t really tell where it came from but then I noticed smoke from the electrical enclosure of the lathe. I am a fairly brave (but stupid) soul and tried it again.
everything was fine and away I went.
to cut a long story short after intermittent bangs and smoke (my reasoning being that maybe condensation was the cause and after it cleared it ran fine) I’ve had a good look at the main switch after ascertaining by smell and found that there is charing/ blackening on the Moeller T20b-1 switch.

Will this just be a failure due to age or is the rotary converter at fault

ps please be gentle with me as I know I am a fool

thanks