Unknown Relays ITT 24A12C19A

A while ago I bought a bunch of relays, about 20+ of which were of the same type. Problem is that I haven't been able to find any data on them online (and I've searched hard).

The model appears to be "24A12C19A", printed on top of the coil, and "78 08" is above it. Made in England by ITT. Coil resistance is about 520R. They work on 24V, but seem a bit sluggish. Shape is the same as a V23154-C series relay.

Thanks for reading.

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Reply to
Computer Nerd Kev
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The 78 08 is probably late February 1978.

I have an old NTE paper catalog ("Relays, Proximity Switches, Circuit Breakers, and Accessories", 7th edition, copyright June 2002) that has a cross-reference for some similar part numbers to NTE/ECG parts.

ITT? P/N NTE/ECG P/N

24A02C14C R16-11D3-12 24A02C14E R16-11D3-12P 24A02C20C R16-11D3-24 24A02C20E R16-11D3-24P

24D02C09C R16-11D5-5

24D02C14C R16-11D5-12 24D02C20C R16-11D5-24

24E02C09C R16-11D5-5

24E02C14C R16-11D5-12 24E02C14E R14-11D10-12P 24E02C20C R16-11D5-24 24E02C20E R14-11D10-24P

25A04C09C R16-17D5-5

25A04C14C R16-17D3-12 25A04C14E R16-17D5-12P 25A04C20C R16-17D3-24 25A04C20E R16-17D5-24P

25D04C14C R16-17D5-12

25D04C14E R16-17D5-12P 25D04C20C R16-17D5-24 25D04C20E R16-17D5-24P

25E04C09C R16-17D5-5

25E04C14C R16-17D5-12 25E04C14E R16-17D5-12P 25E04C20C R16-17D5-24 25E04C20E R16-17D5-24P

26A06C14C R16-23D5-12

26A06C20C R16-23D5-24

The NTE/ECG parts with 11D3, 11D5, and 11D10 are DPDT; 17D3, 17D5, and

17D10 are 4PDT; 23D5 are 6PDT. This seems to correspond to the third and fourth numeric digits in the ITT? part number: xxx02xxxx . Yours would be a 12PDT by this logic; does it have 36 contact pins?

The last numbers in the NTE/ECG parts are the DC coil voltages. It looks like the last two numeric digits in the ITT? part numbers are a code for the coil voltage, but your value of '19' isn't listed.

The NTE/ECG numbers of the form R16-xxxx-xx have a 3-48UNC screw sticking out of the bottom, between the coil pins and the contact pins. The R16-xxxx-xxP don't have this screw. This seems to match the C or E suffix on the ITT? part number.

The R16 relays with D3 in the NTE/ECG part number are 3 A at 28 V DC or

120 VAC. The R16 relays with D5 in the NTE/ECG part number are 5 A under the same conditions. The R14 relays with D10 in the NTE/ECG part number are 10 A at 240 V AC, plus some other ratings.

I hope this helps!

Matt Roberds

Reply to
mroberds

From snipped-for-privacy@att.net Wed May 21 18:13:05 2014 Path: aioe.org!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: snipped-for-privacy@att.net Newsgroups: sci.electr>> The model appears to be "24A12C19A", printed on top of the coil, and

Ah yes, of course.

Nice thinking, but they're DPDT with six pins.

Though you might guess that it's between 12V and 24V. Which is strange as they seem slow at 24V. Perhaps that's just their nature.

My ones have a screw there, not sure what that means with the "A" suffix though...

Thanks, it's a lot more than I've gathered from Google searches.

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Reply to
Computer Nerd Kev

I guess the first 1 in your part number (xxx1xxxxx) means something else. The 2 right after that could still mean DPDT.

Have you tried the coil polarity both ways to see if it makes a difference? How about in different orientations of the relay?

This is maybe less likely, but have you tried some small AC voltages? You might want to do this with just one relay, and mark it, as it is likely to get unhappy if it isn't designed for AC.

Matt Roberds

Reply to
mroberds

The relay works equally with either polarity and in all orientations. They still switch at 12V, so I figure 24V must be close to the right voltage if not actually it.

I'm not really motivated enough to dig through transformers/plugpacks or rig up an amplifier for my function generator in order to test with various AC voltages. Especially as I'm not sure how you'd be sure that it was meant for them even if it worked to some extent. How would you know how hot the coil is meant to get for example?

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Computer Nerd Kev

Computer Nerd Kev scribbled thus:

If you can see into the relay, assuming transparent case. You will see a copper shading ring around the top of the pole piece on an AC relay. This shading ring will also create the slugging effect that you describe when using DC on an AC relay.

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Best Regards: 
                     Baron.
Reply to
Baron

It has a clear case, but comparing to a known 32VDC V23154-C series relay I can't see any difference as you describe. I don't have an AC relay of the same design to compare though.

When I have more time, I'll try to find one of those free image hoasting sites and put some pictures up.

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Computer Nerd Kev

Computer Nerd Kev scribbled thus:

The shading ring effectively creates a short circuit turn in which the eddy current magnetic field holds the armature down. A similar effect to dropping a copper coin between two magnets.

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Best Regards: 
                     Baron.
Reply to
Baron

Here are some pictures. TinyPic kept throwing up server errors, so I switched to "Image Posting" after the second picture.

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Computer Nerd Kev

Computer Nerd Kev scribbled thus:

Hi Kev, Thanks for the pics. I see no sign of shading rings ! So those would seem to be DC telecom type relays. If so I would have thought that the coil voltage would be more like 48 volts.

You could try putting say 12 volts AC across the coil. If they turn into buzzers then they are definitely DC only.

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Best Regards: 
                     Baron.
Reply to
Baron

They still work at 12V (just). That would be a pretty wide range of operating voltage.

That they do.

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Computer Nerd Kev

Computer Nerd Kev scribbled thus:

That confirms that they are DC only and dont have a diode across the coil. So it seems that they are 24 volt actuated. :-)

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Best Regards: 
                     Baron.
Reply to
Baron

OK, I'll keep my "prob. 24V" stickers on their component draws then.

Thanks for the help.

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Reply to
Computer Nerd Kev

Computer Nerd Kev scribbled thus:

Your welcome ! Glad to have helped.

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Best Regards: 
                     Baron.
Reply to
Baron

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