PO Type 600 Relays - UK Vintage Radio Repair and Restoration Discussion Forum

M0FYA Andy · 22nd Jan 2018, 11:04 am

Does anyone know whether PO600 relays, the 'little brother' of the more common PO3000 type, ever came with high current contacts, in the way that the PO3000 did?
I'm trying to reverse-engineer a unit which has been robbed of most of its internals to make a replica. According to the circuit, this has three relays. I also have a poor line-drawing which shows that they were PO type, but it's clear that there isn't room for PO3000s, so they must be PO600s.

They switch the current to a quite chunky motor at 24 volts in a radar scanner.

Looking through my stock of PO600 relays, they all have the standard contacts, each with two little 'pips', hence my question. Am I looking for 'unobtainium'?

Many thanks,

Andy

bc312 · 22nd Jan 2018, 4:07 pm

Andy - paragraph 1 of the attached suggests that 600-type relays were not designed for current carrying use. Certainly my own experience was that switching of current required the heavier contact sets fitted on the 3000-type relays. Someone may of course know different.

http://www.uax.me.uk/ta-b5154.pdf

Mike

barrymagrec · 22nd Jan 2018, 4:17 pm

It seems possible that a manufacturer could have used the 600-type frame to make a power relay that was not GPO approved.

Bill · 22nd Jan 2018, 5:22 pm

I think I remember a PO 600 with a fancy 2pole mercury tilt switch fitted, probably hen's teeth now and would only work in certain orientation. Would switch a lot of amps though and be right dangerous if mercury leaked out!
Bill

ETA.I recall It was in a piece of GPO kit, not necessarily telephone use, in its own steel case. Might have been part of an alarm or clock system.

And another thing: haven't I seen this type of relay with standard microswitches instead of contacts- they'd be good for a few amps?

M0FYA Andy · 22nd Jan 2018, 5:56 pm

Thanks for the replies. There wouldn't be room for anything other than normal contacts, but they would have to be able to cope with maybe 4 amps.

VT FUSE · 22nd Jan 2018, 6:20 pm

Possibly a bit wide of the mark,the PYE Cambridge and Westminster had mini power relays close to the 600 style and,if my memory serves,would switch a few Amps.

Maybe worth considering if you need several with 12V coils as many parts chassis must be languishing in attics and sheds?

M0FYA Andy · 22nd Jan 2018, 9:05 pm

If they were genuine PO600 types, I could swap coils. Two need to operate on 24v, so I think 400 or 500 ohm coils will be correct. The other I'm not sure, it is between the anode of an EF50 and HT, I suspect maybe 10,000 to 20,000 ohms.
Information is a bit piecemeal, I have a circuit, but not all components have their values marked!
The unit in question is an Oscillator Type 217. In another thread a couple of weeks ago I asked if anyone had one, but no response at all. I've managed to borrow one with most internals missing to photograph and measure, and it does have a few components present which provide valuable information not on the circuit.

Andy

noble kiwi · 22nd Jan 2018, 10:57 pm

Londex in the UK and Relays pty Ltd in Australia and New Zealand, manufactured relays with substantial contacts by using the 300o type assembly fitted with an extension. It is very likely and logical that the 600 type could have been used accordingly.

M0FYA Andy · 23rd Jan 2018, 9:35 am

Beefy high-current contacts certainly exist for PO3000 type, where the contact itself is circular and the width of the spring as opposed to the more common two little pips. No extension needed! I have a number of these.
But I haven't seen the same concept for PO600's!

22nd Jan 2018, 11:04 am	#1
M0FYA Andy Nonode Join Date: May 2007 Location: Preston, Lancashire, UK. Posts: 2,511	PO Type 600 Relays Does anyone know whether PO600 relays, the 'little brother' of the more common PO3000 type, ever came with high current contacts, in the way that the PO3000 did? I'm trying to reverse-engineer a unit which has been robbed of most of its internals to make a replica. According to the circuit, this has three relays. I also have a poor line-drawing which shows that they were PO type, but it's clear that there isn't room for PO3000s, so they must be PO600s. They switch the current to a quite chunky motor at 24 volts in a radar scanner. Looking through my stock of PO600 relays, they all have the standard contacts, each with two little 'pips', hence my question. Am I looking for 'unobtainium'? Many thanks, Andy

22nd Jan 2018, 4:07 pm	#2
bc312 Pentode Join Date: Feb 2005 Location: Longfield, Kent, UK. Posts: 240	Re: PO Type 600 Relays Andy - paragraph 1 of the attached suggests that 600-type relays were not designed for current carrying use. Certainly my own experience was that switching of current required the heavier contact sets fitted on the 3000-type relays. Someone may of course know different. http://www.uax.me.uk/ta-b5154.pdf Mike __________________ Leave me alone - I know what I'm doing. BVWS member, EUG, G-QRP Radio Bygones/Radiophile

22nd Jan 2018, 4:17 pm	#3
barrymagrec Octode Join Date: Dec 2017 Location: Morden, Surrey, UK. Posts: 1,560	Re: PO Type 600 Relays It seems possible that a manufacturer could have used the 600-type frame to make a power relay that was not GPO approved.

22nd Jan 2018, 5:22 pm	#4
Bill Pentode Join Date: Dec 2005 Location: Denton, Manchester, UK. Posts: 188	Re: PO Type 600 Relays I think I remember a PO 600 with a fancy 2pole mercury tilt switch fitted, probably hen's teeth now and would only work in certain orientation. Would switch a lot of amps though and be right dangerous if mercury leaked out! Bill ETA.I recall It was in a piece of GPO kit, not necessarily telephone use, in its own steel case. Might have been part of an alarm or clock system. And another thing: haven't I seen this type of relay with standard microswitches instead of contacts- they'd be good for a few amps? Last edited by Bill; 22nd Jan 2018 at 5:38 pm. Reason: Thinking about it!

22nd Jan 2018, 5:56 pm	#5
M0FYA Andy Nonode Join Date: May 2007 Location: Preston, Lancashire, UK. Posts: 2,511	Re: PO Type 600 Relays Thanks for the replies. There wouldn't be room for anything other than normal contacts, but they would have to be able to cope with maybe 4 amps.

22nd Jan 2018, 6:20 pm	#6
VT FUSE Hexode Join Date: Aug 2010 Location: Malvern, Worcestershire, UK. Posts: 347	Re: PO Type 600 Relays Possibly a bit wide of the mark,the PYE Cambridge and Westminster had mini power relays close to the 600 style and,if my memory serves,would switch a few Amps. Maybe worth considering if you need several with 12V coils as many parts chassis must be languishing in attics and sheds?

22nd Jan 2018, 9:05 pm	#7
M0FYA Andy Nonode Join Date: May 2007 Location: Preston, Lancashire, UK. Posts: 2,511	Re: PO Type 600 Relays If they were genuine PO600 types, I could swap coils. Two need to operate on 24v, so I think 400 or 500 ohm coils will be correct. The other I'm not sure, it is between the anode of an EF50 and HT, I suspect maybe 10,000 to 20,000 ohms. Information is a bit piecemeal, I have a circuit, but not all components have their values marked! The unit in question is an Oscillator Type 217. In another thread a couple of weeks ago I asked if anyone had one, but no response at all. I've managed to borrow one with most internals missing to photograph and measure, and it does have a few components present which provide valuable information not on the circuit. Andy

22nd Jan 2018, 10:57 pm	#8
noble kiwi Pentode Join Date: Jan 2011 Location: Auckland New Zealand Posts: 175	Re: PO Type 600 Relays Londex in the UK and Relays pty Ltd in Australia and New Zealand, manufactured relays with substantial contacts by using the 300o type assembly fitted with an extension. It is very likely and logical that the 600 type could have been used accordingly.

23rd Jan 2018, 9:35 am	#9
M0FYA Andy Nonode Join Date: May 2007 Location: Preston, Lancashire, UK. Posts: 2,511	Re: PO Type 600 Relays Beefy high-current contacts certainly exist for PO3000 type, where the contact itself is circular and the width of the spring as opposed to the more common two little pips. No extension needed! I have a number of these. But I haven't seen the same concept for PO600's!