Strand Dimmer Identification

[fliggygeek]

I am trying to identify this dimmer, (See attached images) There are 5 of them being used as house light dimmers at an auditorium here in Tasmania Australia. They are not DMX as far as we know, being set using three sets of three switches. for each section of the three sections of house lights, you can press one switch for full, one for a preset level as set on the knob on the dimmers, and one for off. Any ideas?http://imgur.com/O3Xcn.jpghttp://imgur.com/6tMsP.jpghttp://imgur.com/6tmGl.jpghttp://imgur.com/CNjh3.jpg

[Ynot]

Can't say for certain, but I suspect these may possibly have been a special from Strand. Can't see anything obvious in the Strand Archive pages, but it might be worth contacting Jon directly to ask if he has any ideas. (His e-mail at the bottom of the archive pages)

[fliggygeek]

Done that already, just waiting for a response.

 

Can't say for certain, but I suspect these may possibly have been a special from Strand. Can't see anything obvious in the Strand Archive pages, but it might be worth contacting Jon directly to ask if he has any ideas. (His e-mail at the bottom of the archive pages)

[Kazeja]

I believe they're single channel STM/JTM in a box.

 

K

[fliggygeek]

If that is the case, what protocol/control wiring system do they use? My ultimate purpose is to make these House lights DMX controllable. (Attempting to make purpose built Demux using microcontroller etc.) Also is there an easy way to identify the STM/JTM if I open the cover?

 

I believe they're single channel STM/JTM in a box.

 

K

[Ynot]

If that is the case, what protocol/control wiring system do they use? My ultimate purpose is to make these House lights DMX controllable. (Attempting to make purpose built Demux using microcontroller etc.) Also is there an easy way to identify the STM/JTM if I open the cover?

 

I believe they're single channel STM/JTM in a box.

There's no way they'll be DMX unless there's already a demux in place - -10v analogue all the way. :D

If they are STM, you can see the channel modules on the archive pages as there's a cutaway on the photos of the 20-way rack there.

[fliggygeek]

10v analogue makes life easy :D, and no, theres no demux. Though we have STM/JTM full size wall mounted system as the LX dimmers downstairs, and they are demuxed. Thanks for that.

 

Another query, is the control system (the momentary switch setup) a common way of using this system?

 

If that is the case, what protocol/control wiring system do they use? My ultimate purpose is to make these House lights DMX controllable. (Attempting to make purpose built Demux using microcontroller etc.) Also is there an easy way to identify the STM/JTM if I open the cover?

 

I believe they're single channel STM/JTM in a box.

There's no way they'll be DMX unless there's already a demux in place - -10v analogue all the way.

If they are STM, you can see the channel modules on the archive pages as there's a cutaway on the photos of the 20-way rack there.

[David Ripley]

If they are STM or even JTM they use 0 to -10v. In any case Strand kit of that age is going to be analogue with that voltage range. In any case you'll need a Demux as previously stated. I guess you wnat to control them from your desk

 

As for the current control system - no, I've not come across it. You say they are switches - do the houselights have an in built fade time or do they snap between states? What is the big cylinder on each module for, it looks a bit odd! Could it be some sort of timing control?

 

Just musing out of interest really

 

Good luck!

 

David

[Richard Bunting]

I am trying to identify this dimmer, (See attached images) There are 5 of them being used as house light dimmers at an auditorium here in Tasmania Australia. They are not DMX as far as we know, being set using three sets of three switches. for each section of the three sections of house lights, you can press one switch for full, one for a preset level as set on the knob on the dimmers, and one for off. Any ideas?

 

Oh dear, oh dear, oh dear.!

what an amazingly neat installation for dimmers that are probably 40+ years old. They are PTUs (which I think stood for Permanent Thyristor Unit?), and these were single 2kW versions of the JTM/STM module in a box. Unfortunately, there are no details on the Strand Archive, but if anyone has access to a Strand Electric catalogue of the late 60's, then they should be in there. Interestingly, you have silver painted (Strand Electric) and green (Rank Strand Electric) versions, which would put them about 1968 / 69. These would have been produced in the UK and shipped to Melbourne for onward sale. For a short period, Rank produced some of their own dimmers and controls in Australia in the seventies, to get around import tax.

There will probably be a -10V PSU in the box linked in to the preset rotary switch, so you should be able to link your demux connection into the control voltage connection on the module.

 

HTH

 

Richard

[fliggygeek]

The houselights are all snap to preset. The circular things are junction boxes AFAIK Similar Picturethis When I say Switches, I mean ones like this

If they are STM or even JTM they use 0 to -10v. In any case Strand kit of that age is going to be analogue with that voltage range. In any case you'll need a Demux as previously stated. I guess you wnat to control them from your desk

 

As for the current control system - no, I've not come across it. You say they are switches - do the houselights have an in built fade time or do they snap between states? What is the big cylinder on each module for, it looks a bit odd! Could it be some sort of timing control?

 

Just musing out of interest really

 

Good luck!

 

David

[Robin D]

You might also want to contact Bruce McRae (or is that MacRea?) in Australia if he's still about. He used to run a lighting company near Armidale, NSW (Mac{something} or Mc{Something} and was a bit of a Strand expert.

[fliggygeek]

Just putting it out there, should I perhaps take some good photos of the dimmer systems here and send them in to the strand archive? im aware that we have some stuff even older than this, not installed, but we have a full dimmer set from the Peacock Theatre (1976), as well as the original control unit for the STM/JTM downstairs.

 

Thanks for the heads up about the Green/Silver, thats interesting, as we have 5 dimmers and only 3 separately dimmed sections. I'm wondering if we could have some older dimmers that have been replaced (ie. green dimmers were originals(JTM)? silvers were upgrades(STM)?)

Any leads as to contact info for this Bruce MacRae or others who might have access to wiring diagrams etc would be greatly appreciated.

 

I am trying to identify this dimmer, (See attached images) There are 5 of them being used as house light dimmers at an auditorium here in Tasmania Australia. They are not DMX as far as we know, being set using three sets of three switches. for each section of the three sections of house lights, you can press one switch for full, one for a preset level as set on the knob on the dimmers, and one for off. Any ideas?

 

Oh dear, oh dear, oh dear.!

what an amazingly neat installation for dimmers that are probably 40+ years old. They are PTUs (which I think stood for Permanent Thyristor Unit?), and these were single 2kW versions of the JTM/STM module in a box. Unfortunately, there are no details on the Strand Archive, but if anyone has access to a Strand Electric catalogue of the late 60's, then they should be in there. Interestingly, you have silver painted (Strand Electric) and green (Rank Strand Electric) versions, which would put them about 1968 / 69. These would have been produced in the UK and shipped to Melbourne for onward sale. For a short period, Rank produced some of their own dimmers and controls in Australia in the seventies, to get around import tax.

There will probably be a -10V PSU in the box linked in to the preset rotary switch, so you should be able to link your demux connection into the control voltage connection on the module.

 

HTH

 

Richard

[boatman]

It might be worth a post on the ALIA forum as well. There may be similar installations in other parts of Oz.

[Robin D]

Google is your friend http://www.macsound.com.au/.

[Brian]

...if anyone has access to a Strand Electric catalogue of the late 60's, then they should be in there. ...

 

TU, PTU Dimmers

Similar dimmer modules, in individual wall-mounting enclosures, are available for controlling auditorium and presentation lighting. TU series are for simple control by a remote lever box. PTU series have an additional printed-circuit card to allow up, down or to preset level multi-position control from parrallel-connected sets of push buttons.

(Strand 1968 Catalogue, alongside STM dimmers.