Fail Safe Operation - AEC AD Series Operation And Installation Manual

2-8-3 Fail Safe Operation

2-8-4 Safety Device Lock-Outs
WARNING!
Always disconnect and lockout all electrical power and pneumatic
(i.e. compressed air) sources prior to servicing or cleaning any
Dryer, including all AD units. Failure to do so may result in serious
injury.
At no time must anyone remove the lockout or reconnect the twist
plug, other than the person who installed the lockout or who
unplugged the twist plug.
2-8-5 Lock-Outs, Plugs, and Other Safety Devices
WARNING!
Disconnect both of these items to ensure optimum maintenance
personnel safety when cleaning or servicing this equipment.
AD Series Dehumidifying Dryers
If a safety device or circuit should fail, the design must be such
that the failure causes a "Safe" condition. As an example, a safety
switch must be a normally open switch. The switch must be held
closed with the device it is to protect. If the switch fails, it will go
to the open condition, tripping out the safety circuit.
At no time should the safety device fail and allow the operation
to continue. For example, if a safety switch is guarding a motor,
and the safety switch fails, the motor should not be able to run.
Some safety devices disconnect electrical energy from a circuit.
The safety devices that are utilized on AD models are primarily
concerned with the pneumatics and electrical power disconnection,
and the disabling of moving parts that may need to be accessed
during the normal operation of the machine.
Some of the safety devices utilize a manual activator. This is the
method of initiating the safety lock out. This may be in the form of
a plug, disconnect plug, lever or a handle. Within this lockable
handle, there may be a location for a padlock. Personnel servicing
the equipment should place a padlock in the lockout handle.
The AD Dryer utilizes several types of safety devices.
The Line Cord Plug
This line cord plug allows the operator or maintenance personnel
to unplug the dryer from its power source and tag it out. This plug
may be tagged with any number of approved electrical lockout
tags. These tags are available at most electrical supply stores.
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