Trinity ACCUVAR, Руководство пользователя, Страница: 23 / 27

pg. 23
TRINITY
ACCUVAR - Operational Manual
To enable the Relay to measure the power factor correctly:
a. The R, Y, B voltage connections must be correct.
b. The voltage must be nearest (10% plus or minus) to the specified voltage for the Relay.
c. The control circuits of the panel, on which the Relay is mounted, are equally important.
Using the built in Manual control is the easiest way to implement the system. It is also the
most economical and trouble free. If user wishes to use external Manual Control, pay
careful attention to signal flow. Push-buttons must be used for the contactors to enable
automatic cutoff in the event of a power failure. Do provide isolating contacts for each
contactor, otherwise the control can lock out in Auto, by feedback over the Manual Bus.
(A). Troubleshooting
The ACCUVAR is robust electronic equipment and must be handled with all the care merited
by it. It is quite rugged and will withstand a few hard knocks, but this cannot make up for the
deficiency in system design.
Repairs at site are not recommended because at most this can only be a patch work, and
sustained reliability is difficult to achieve with a site repaired Relay. This section on
Troubleshooting therefore deals with fault finding in the system and to establish whether the
Relay is defective or whether it is a system problem. If the fault is seen to lie entirely with the
Relay, it will have to be sent to factory for repairs.
System faults can be classified into three categories:
• Those related to the basic configuration of the system.
• Those related to the errors and mistakes in the implementation of the system design
• Those related to the faults in the actual equipment
a. Faults related to the actual system design:
The most common faults are:
External Manual Control not implemented properly,
Here many designers provide a
‘Starter-relay’ configuration for the manual control, and
just bring the connection from the relay contact to the contactor.
There are two problems with this:
i. Timing function is not provided from Manual control.
ii. The scheme does not work in Auto ode. The remedy is to examine the drawings and
make changes at site. The temporary remedy is to change the relay mode to Manual,
and use the panel manually. The better alternative is to change the control wiring to
incorporate suitable isolating contacts, timers etc. to make a proper system.