air conditioned.
c) The panel board contains individual starter for individual motor consisting set
of hardware like switch fuse unit, contactor, local start/stop button and
indi cations lamps on the front door of the starter. In addition to above, it has
an intelligent process control unit (an intelligent controller) which provides
intelligent motor protection and starter process control system.
d) The intelligent control unit in each starter is capable to interface all the starter
signals and provides process control functions to respective equipment as per
requirement in addition to intelligent motor protection features.
e) Intelligent motor control centre is an advance version of conventional motor
control centre used for group process control function where set of equipment
are required to operate in sequential mode to perform a certain process task.
In this case, process activity of an equipment is interdependent to its
predecessor and successor equipment and it cannot perform its function alone.
f) The motor is started from operator station in group mode to start the process.
The motor starter takes care of motor protection as well process interlocks
for the respective equipment. However, entire process is controlled centralized
DCS system but in this case DCS only provides specific process control loops
for the respective equipment which are not possible by the intelligent starter
unit. The central processing unit is equipped with pre-loaded program to perform
the process functions. HMI (human machine interface) is used to interface
between machine (through DCS) and plant operator.
g) All motor starter signals are interfaced with DCS system with single communication
cable instead of centrally located input/output interface stations. This I/O
d evice is not used with intelligent MCC since every starter has intelligent CPU
with requisite input/output modules and capable to interface digital signals
and analogue signal at its level.
h) Local operation of individual equipment is only envisaged for maintenance
and inspection purpose. Always remote operation is envisaged for process
operation mode through distributed control system.
i) The intelligent MCC offer intelligent motor protection with conditioning
monitoring parameters like kW, kWH, kVAR, Power Factor, Line Current,
Voltage, Frequency, %THD, apart from thermal, single phase, over current,
earth fault, stall protections.
j) The integrated motor control station has following key features:
- The system is costlier than conventional integrated motor control centre
by 16% to 20% but same is compensated in the cost of DCS since input/out
put marshalling panels are not required to interface the MCC with DCS, - The system is intelligent and totally controlled with individual processing unit,