Appendix 5: External Over Load Relay Applications - Toshiba 18 - 1250 A Instruction Manual

TE Series
Appendix 5 – External Overload Relay Applications
Digital Solid State Soft Starters 18 – 1250A
Your TE Series starter comes equipped with a very intelligent internal
electronic overload protection system, and does not need an external
Over Load Relay (OLR). There are instances however where external
OLRs are needed or desired because of the application. These fall into
three categories; Higher Level Protection systems, Redundant Backup
applications and Special Motor applications.
NOTE:
If the Decel Function is activated (F024), additional consideration
must be put into determining how the starter is to operate in the
event of an Over Load Trip. See Section 5.6.5 for issues regarding
this application.
HIGHER LEVEL PROTECTION SYSTEMS
Because of a desire for uniformity and/or operator familiarity in some
facilities, Motor Protection Relays or other coordinated OEM protection
systems may be used in lieu of the TE Series protection (even though
most of the features are the same or better). In these instances the TE
Series Over Load protection can simply be turned off, deferring
protection to the external devices. Care should be taken however to
ensure that the external device is properly wired into the starter control
circuit to facilitate shutdown of the motor. The TE Series provides a
PTC input that can be wired to the NC aux contact of the external
device so that a trip will still shut down the TE Series and be
annunciated on the display. See section 4.7.2.a for more details on
using the PTC input.
REDUNDANT BYPASS STARTER APPLICATIONS:
In some applications, it may be necessary to provide an independent
means of starting and protecting the motor should be TE Series starter
become inoperable. If this were the case, the Bypass Contactor could
be used for Across-the-Line (D.O.L) starting of the motor. The TE...BP
version with Integral Bypass Contactors is designed for that possibility,
as long as the starter is properly selected when ordered. To do so,
select the starter based upon the ATL (Across-the-Line) selection chart
so that the contactor is rated for ATL duty instead of the normal Shunt
Duty (see section 1.2.3 for Selection charts).
Under normal operations, the Bypass Contactor is controlled internally
by the TE Series PC board and an internal pilot relay. For redundant
backup purposes however, terminals B1 and B2 of TB4 are provided for
field connection of a dry contact closure in parallel to the pilot relay
contact, allowing control even if the electronics are out of service. AC
control power must still be applied to TB2 terminals A1 and A2, but no
other electronics or power supplies need to be functioning. It is in this
instance that an external OLR must be added to the motor power circuit
and wired into that coil control circuit. TB4 is located in different areas of
each frame size in the TE Series. Refer to the following diagram for the
location on your unit.
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