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Application – Three-Phase Motors
Overload Protection of Three-Phase Submersible Motors
The characteristics of submersible motors are different
than standard motors and special overload protection
is required.
If the motor is locked, the overload protection must trip
within 10 seconds to protect the motor windings. Subtrol/
SubMonitor, a Franklin-approved adjustable overload
relay, or a Franklin-approved fi xed heater must be used.
Fixed heater overloads must be the ambient-compensated
quick-trip type to maintain protection at high and low
air temperatures.
All heaters and amp settings shown are based on total
line amps. When determining amperage settings or
making heater selections for a six-lead motor with a
Wye-Delta starter, divide motor amps by 1.732.
pages 28, 29 and 30 list the correct selection and
settings for some manufacturers. Approval for other
manufacturers’ types not listed may be requested by
calling Franklin’s Submersible Service Hotline at
800-348-2420.
Refer to notes on page 29.
HP KW VOLTS
NEMA
STARTER
SIZE
HEATERS FOR
OVERLOAD RELAYS
ADJUSTABLE
RELAYS
(NOTE 3)
FURNAS
(NOTE 1)
G.E.
(NOTE 2) SET MAX.
1/2 0.37
200 00 K31 L380A 3.2 3.4
230 00 K28 L343A 2.7 2.9
380 00 K22 L211A 1.7 1.8
460 00 - L174A 1.4 1.5
575 00 - - 1.2 1.3
3/4 0.55
200 00 K34 L51CA 4.1 4.4
230 00 K32 L420A 3.5 3.8
380 00 K27 L282A 2.3 2.5
460 00 K23 L211A 1.8 1.9
575 00 K21 L193A 1.5 1.6
1 0.75
200 00 K37 L618A 5.0 5.4
230 00 K36 L561A 4.4 4.7
380 00 K28 L310A 2.6 2.8
460 00 K26 L282A 2.2 2.4
575 00 K23 L211A 1.8 1.9
1.5 1.1
200 00 K42 L750A 6.3 6.8
230 00 K39 L680A 5.5 5.9
380 00 K32 L420A 3.3 3.6
460 00 K29 L343A 2.8 3.0
575 00 K26 L282A 2.2 2.4
2 1.5
200 0 K50 L111B 8.6 9.3
230 0 K49 L910A 7.5 8.1
380 0 K36 L561A 4.6 4.9
460 00 K33 L463A 3.8 4.1
575 00 K29 L380A 3.0 3.2
3 2.2
200 0 K55 L147B 11.6 12.5
230 0 K52 L122B 10.1 10.9
380 0 K41 L750A 6.1 6.6
460 0 K37 L618A 5.1 5.5
575 0 K34 L510A 4.1 4.4
5 3.7
200 1 K62 L241B 19.1 20.5
230 1 K61 L199B 16.6 17.8
380 0 K52 L122B 10.0 10.8
460 0 K49 L100B 8.3 8.9
575 0 K42 L825A 6.6 7.1
7.5 5.5
200 1 K68 L332B 28.4 30.5
230 1 K67 L293B 24.6 26.4
380 1 K58 L181B 14.9 16.0
460 1 K55 L147B 12.3 13.2
575 1 K52 L122B 9.9 10.6
10 7.5
380 1 K62 L241B 19.5 21.0
460 1 K60 L199B 16.1 17.3
575 1 K56 L165B 12.9 13.6
Class 10 Protection Required
Table 28 - 60 Hz 4" Motors
28