8.2.7 Safety Interlock
The AT Series safety interlock has been designed to be used with the Voltech Safety System, which is based on the use of a light curtain. Details of this accessory are available from your Voltech distributor.
Alternatively, it may be connected into your own safety system as described in the following pages.
DANGER OF ELECTRIC SHOCK
Once the interlock has been connected, the AT Series Tester may produce high voltages that should be considered lethal.
It is always the responsibility of the user to ensure adequate safety measures are taken in accordance with local regulations.
Contact your Voltech supplier for details of approved safety systems, if in any doubt.
9-pin female D-type connector.*
There are 3 active circuits on the safety interlock connector. Two are digital control circuits, and the third is a high voltage analog circuit.
ALL three circuits must be correctly made before the AT Series Tester will generate accessible dangerous voltages.
If any of the circuits are ‘broken’ during use, dangerous voltages, which could be applied to the transformer under test, are actively reduced and quickly made safe.
*NOTE: A slim connector shell is required to fit the AT3600 aperture. Example
type: McMurdo 51218-1
HVOP and HVIP (Pins 3 and 7)
The HVOP is an analog voltage output which can be as high as 400V.
The HVIP is a corresponding input voltage. All the high voltage test signals used by the AT Series Testers are derived from this input.
In the ‘safe’ condition, HVOP is linked back into HVIP.
LB0 and LB1 (Pins 5 and 9)
These are the two digital control signals.
In the ‘safe’ condition, !LB0 is linked to 0v, and LB1 is driven to a voltage between +4.5V and +5V.
LID0 and LID1 (Pins 4 and 8)
These are two further digital control outputs used by the Voltech Safety System.
Connection to Your Safety System
The following diagram shows the principles of how to construct your own safety system based on the signals available on the Safety Interlock connector
NOTES: Your safety system must contain all three switches, as shown in the diagram. If any switch is in the open position (as shown), the Tester will not produce any voltages greater than 20V peak, at the test nodes on the top face. The connection between pins 3 and 7 must be made with a relay rated at 400V 2ARMS. The relay must be situated no more than 1.5metres from the Tester’s safety interlock connector. Timing requirements of any safety system must conform to the spec section of chapter 10.
||DO NOT ROUTE OVER LONG DISTANCES.
DO NOT ATTEMPT TO ROUTE LINE POWER (230/110V)
THROUGH THESE INTERLOCKS.