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Attempted to get details on what looked like the device on the site mentioned above. I got a this is not available to thee response.

So from other pix at that site, I am currently guessing that the 'front' side of the device has red and green buttons that provide the mechanical 'set' function. The green button closes the contact and the relay holds. The red button opens the contacts. Power failure drops the relay and the contacts open until the green button is again pushed. Pure conjecture, but it makes sense. Soooo a pix of the non visible 'front' side would be enlightening(or a wet towel). This implies the coil is across the 'equipment' terminals.

I see no relevance to the Zettler relay. An entirely different animal.

The atc device would be a N/O Form A.

Note that the "Must Operate" voltage is 82.5 volts. DOES THAT MEAN THAT ANY VOLTAGE APPLIED THAT IS GREATER THAN THAT WILL ENERGIZE THE RELAY?

dusty wrote:Note that the "Must Operate" voltage is 82.5 volts. DOES THAT MEAN THAT ANY VOLTAGE APPLIED THAT IS GREATER THAN THAT WILL ENERGIZE THE RELAY?

The note also 'states' that it MAY "operate" at a voltage lower than the MUST voltage.

Unless I am missing something the Zettler relay info is an irrelevant search.

JPG wrote: Unless I am missing something the Zettler relay info is an irrelevant search.

JPG,

I only looked up the Zettler relay because I couldn't find any search that turned up info on the the ATC part #. If you look closely at the pic you can see that the Zettler relay is mounted and there is epoxy encapsulating it on the top, so presumably there are more electronics inside of it (otherwise why encapsulate?). Not a lot of details to go on here, but if you look at the pics of switches for sale on that UK website and look again at this ATC part, I am reasonably sure that this ATC part is mounted somewhere inside the Mark V and the main power switch is connected via leads to this ATC part (power switch is separate from this power loss disconnect). At least that would be my guess based on the limited information we have here.

This is an old thread, but Matt (Locmine) posted on May 27th, 2020 saying he had this same issue. Perhaps Matt can reply with more information and hopefully some more pics of this device in action.

OK, fergit thet red/green button conjecture!!!

The Zettler relay is a component of the atc device.

So without understanding what is on the pcb side of the relay we be reduced to pure speculation.

I will have to ponder what Dennis suggested later. That implies(I think-sorta) that the device is connected up stream from the power switch?

The mounting appears to be surface mount.

Yes RFGUY I finally came around to why the Zettler IS relevant.

I reached out to the manufacturer and I was able to obtain the datasheet below for this power loss disconnect. It is an obsolete part and there is no replacement (at least not from ATC). Based on the description in the datasheet, it does function as some of us suggested it might. There is a separate on/off switch which is the headstock power switch. After a power loss event, if the on/off switch was left in the on position then the Mark V will not power on until you power cycle it (on-->off --> on). A power loss event has to be greater than 0.15s in duration to trigger this disconnect. Don't know if this helps anyone who happens to have a Mark V with this ATC power loss disconnect, but at least it de-mystifies what the device was and its intention...

RFGuy wrote:I reached out to the manufacturer and I was able to obtain the datasheet below for this power loss disconnect. It is an obsolete part and there is no replacement (at least not from ATC). Based on the description in the datasheet, it does function as some of us suggested it might. There is a separate on/off switch which is the headstock power switch. After a power loss event, if the on/off switch was left in the on position then the Mark V will not power on until you power cycle it (on-->off --> on). A power loss event has to be greater than 0.15s in duration to trigger this disconnect. Don't know if this helps anyone who happens to have a Mark V with this ATC power loss disconnect, but at least it de-mystifies what the device was and its intention...

SP0303-240.pdf

Nice work, RFGuy!