Suggested Settings; Lv/Hv; Mult; Oc - Motor Saver SymCom 77C Installation Instruction

SUGGESTED SETTINGS

Consult the motor manufacturer for recommended settings. Refer to the PROGRAMMING
EXAMPLES section for additional assistance.

LV/HV-

The recommended settings for LV
(low voltage) and HV (high voltage)
depend on many factors such as
motor usage, motor size,
environmental factors and
tolerance of the motor. The motor
manufacturer should be consulted
for HV and LV settings. However,
the NEMA MG1 standard
recommends that LV and HV be
set to no more than ±10% of the
motor's nameplate voltage. The
setting can be determined by multiplying the motor's nameplate voltage by the
recommended percent over and under voltage. (e.g., The motor nameplate voltage
is 230V, set LV to 0.9x230=207, set HV to 1.10x230=253)
NOTE: LV cannot be set higher than HV – HV may have to be adjusted higher before
the proper LV setting can be programmed.

MULT-

MULT is the multiplication factor for determining true current settings and
represents the number of conductors passing through the main current window
marked B, or current transformer ratio of external CTs. The appropriate number can be
determined from Table 1 on page 1. MULT must be correctly programmed in
order to accurately program the current settings.

OC-

OC Represents the motor's maximum service factor amperage. The OC (overcurrent)
setting depends on many factors such as motor usage, motor size, environmental
factors and tolerance of the motor. The motor manufacturer should be consulted for
OC settings. However, OC is typically between 110% and 125% of full load amperage
(FLA).
UC- The UC (undercurrent) setting is typically set to 80% of full load amperage (FLA). The
overload relay with a UC setting of 80% of FLA will typically detect a loss of load for
many pumps and motors such as a dry-well condition for submersible pumps. The UC
setting may be set to 0.00 to disable undercurrent (loss of load) protection.
TC- TC designates the trip class for overload protection. The trip class defines the trip
delay when an overload is detected. Trip class is determined by the type of motor
and application. The motor manufacturer should be consulted for the proper setting.
Table 4 shows the trip classes and gives general application descriptions.
RD1- RD1 is the rapid-cycle timer. It will engage when the motor is first powered-up and
after the motor controls shut down the motor. An RD1 setting of 20-30 seconds will
generally protect the motor from rapid, successive power outages or short cycling
caused by the motor controls. A setting of 0 seconds will allow the motor to start
immediately after power-up or normal shutdown.
RD2- RD2 is the restart delay after the overload relay trips on overload. This delay allows the
motor to cool down after experiencing an overcurrent. It is also known as a motor cool-
down timer. The motor manufacturer should be contacted to determine this setting.
Under normal circumstances, a setting of 5-10 minutes will give the motor enough time
to cool down between faults.
RD3- RD3 is the restart delay after an undercurrent. It is also known as a dry-well recovery
timer and is usually used in submersible pumping applications. The setting of RD3
depends on the recovery time of the water well and varies widely from application to
application.
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10/05