Member postings for Martyn Stevens

Update

.http://cinerdistan.com/2-uncategorised/617-engineering

This link should enable access to a special page I have added to my website with a couple of pix to show the motor and the very restricted access. I'm certainly not going to try anything until it's a lot cooler, but I will consider taking the back off and looking at the centrifugal switch, if such there be. I shall also have a look at the main switch to check if there is arcing. If I find any info about the motor, I will add to this thread, but at the moment I can see no legible info anywhere on the motor or the capacitor, so I'm just going to wait for a bit until a) it's cooler and b) I feel strong.- at the moment I can still get by.

Thanks again for all the comments and suggestions

Martyn

Thank you all for your comments. Here is a progress report.

I removed the cover to the box on top of the motor. The wiring seemed a bit awkwardly done and the plastic base for the connectors was partly melted. One wire, between a microswitch and a red pushbutton on the outside of the box, was almost rotted thru so I replaced that. I disconnected then reconnected the capacitor and put everything back together. The hesitant start-up has gone, but it don't sound quite right and there is still that "missing" and the intermittent thumping noises.

I was interested in the comments about automatic centrifugal switching of the capacitor, which is a feature of Debrie projectors and there is indeed a very characteristic "click" as the motor runs down.I have fixed one or two of these so may be able to figure out what to do. I am puzzled, however, by some aspects of this. Most older sound projectors, where a fairly constant speed is necessary, use an induction motor with a start/run capacitor, which is always in circuit. My experience of the Debrie and a few other machines that use a start cap and a centrifugal switch is that if the centrifugal switch fails, it very quickly leads to destruction of the cap circuit - afterwards, the motor is still capable of running but will not start on its own. If this is the problem, why is the motor still working?

I will do some pix of the motor and probably put them on my website. One of my problems here is that access to the motor is very restricted and my ability to work in confined spaces is very limited nowadays. Also, like I suspect most hobbyists, I have far to many things/projects to do than I am likely to complete in my lifetime and I really don't need this. Nor did I (or my wife, I suppose) need for her to fall over and break her upper arm, naturally on the dominant side, leaving her severely incapable for a couple of months. I am temporarily a carer and housekeeper. Life? Don't talk to me about life!

Rob,

Hi. Hope you have much time on your hands if you mean to browse my site..... There are some problems with the site; just contact me if you need to.

You might like to search for Moviestuff, an American company who make (hugely expensive) digital transfer machines - I own part of a Mark One, now increasingly obsolescent.

I am assuming this is an electronics question!

I have a Harrison 11" retro-fitted, I presume, with a 240v motor. There are just go and stop buttons. The motor has a small box on top plus what looks like a capacitor.

Recently I have noticed intermittent slight hesitations (a bit like a car "missing" on one cylinder), accompanied by a sort of quiet knocking noise.

My immediate assumption was that the capacitor was at fault, because the machine then began failing to start properly - it hesitated, then got up to speed after a few seconds.

However, I have no info whatever about the motor or the capacitor, with no legible markings on either. My capacitor tester says 38mf, but I do not know if this is significant.

Is my diagnosis likely to be correct?

How can I establish the rating of a) the capacitor and b) the motor?

If the worst comes to the worst and the motor is defective, what do I need to know to specify a replacement?

Any guidance would be much appreciated.

Edited By Martyn Stevens on 17/07/2021 12:54:34

Hi,

My main hobby is actually the collection and renovation of old cine equipment - I have a website, www.cinerdistan.com.

A reasonably equipped workshop is an essential aid. I have a Harrison 11", a generic modern vertical mill plus stuff like a bandsaw, sander and now a folder. I have had to learn everything I know (fairly limited) from books and trial and error - it seems impossible to get trained nowadays. I am retired, over 70 and in relatively poor health. Fortunately Covid has largely passed me by so far, as lockdown is not that different from what O would normally do. Any questions I ask in forums are going to be simple for most of you I suspect.

Martyn Stevens

Hi,

I'm new around here. I have a Harrison 11", and would love to fit DRO but have no idea where or how to drill holes. I have absolutely zero precision of eye, which is why I use tools! and am afraid of drilling holes in my machine that would, if I got it wrong, make it next to impossible to fit the DRO. Does anyone have specific experience of fitting DRO to this machine? What scale lengths do I need?

Please bear in mind that I am not very good at this - I've hed to pick uip what I could without much help and have problems understanding all sorts of stuf the cognoscenti take for granted!

Martyn Stevens