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What is a 1AD driver?

deonb

Member
Joined
Nov 1, 2020
Messages
6
Location
Redmond WA
My Genie and EV10 controller has controls for F, R and 1A/1AD.

What does 1AD do?

I've seen various descriptions on the web about 1A in regards to SCR controllers, but nothing describing what 1A is.
 

Txhayseed

Senior Member
Joined
Dec 23, 2019
Messages
610
Location
Texas
So can you tell us what particular genie unit you have and a serial# genie has alot of cross over. Really helps to know what you actually got. Have you pulled the schematic and seen where it went from the controller ??
 

deonb

Member
Joined
Nov 1, 2020
Messages
6
Location
Redmond WA
So can you tell us what particular genie unit you have and a serial# genie has alot of cross over. Really helps to know what you actually got. Have you pulled the schematic and seen where it went from the controller ??

I have a Z-30/20HD. If you look at the Operating & Maintenance manual (page 52) - there are two similar looking devices next to each other. A PMTD (Pulse Monitoring Trip Delay) and a 1A.

The PMTD is documented as:
"Senses SCR short - Delay allows ground connection only if SCR OK"

Perfect. That makes sense. However the 1AD is documented as:
"Senses 1A contact short allows ground connection only if 1A OK"

That doesn't help me if I don't know what a 1A is in the first place...
 

BillG

Senior Member
Joined
Mar 26, 2009
Messages
510
Location
S. Wisconsin
The term "1A" dates from a long time ago, probably near 100 years, it is used as a way to indicate the normal sequence of operation in relay / contactor circuits developed by GE. 1A in your circuit stands for number one auxiliary or in later terms the bypass contactor. When it is energized the entire SCR control is out of the circuit or bypassed. In other words power is applied from the battery through the forward or reverse contactor the motor and the 1A contactor. The SCR control is dead (mostly as far as motor power is concerned) when the 1A is energized. The 1AD or 1A driver energizes the 1A contactor via the oscillator card.
 
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