AIM Manual

Motor Application » Three-Phase Motors (Page 29)

Overload Protection

Overload Protection of Three-Phase Submersible Motors

Class 10 Protection Required

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 fixed 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 29, 30 and 31 list the correct selection and settings for some manufacturers. Approval for other manufacturers’ types not listed may be requested by calling Franklin’s Technical Service Hotline at 800-348-2420.

Refer to notes on page 30.

Table 29 - 60 Hz 4" Motors

HP	KW	VOLTS	NEMA STARTER SIZE	HEATERS FOR OVERLOAD RELAYS		ADJUSTABLE RELAYS (NOTE 3)
HP	KW	VOLTS	NEMA STARTER SIZE	FURNAS (NOTE 1)	G.E. (NOTE 2)	SET	MAX
1/2	0.37	200	0	K31	L380A	3.2	3.4
		230	0	K28	L343A	2.7	2.9
		380	0	K22	L211A	1.7	1.8
		460	0	-	L174A	1.4	1.5
		575	0	-	-	1.2	1.3
3/4	0.55	200	0	K34	L510A	4.1	4.4
		230	0	K32	L420A	3.5	3.8
		380	0	K27	L282A	2.3	2.5
		460	0	K23	L211A	1.8	1.9
		575	0	K21	L193A	1.5	1.6
1	0.75	200	0	K37	L618A	5	5.4
		230	0	K36	L561A	4.4	4.7
		380	0	K28	L310A	2.6	2.8
		460	0	K26	L282A	2.2	2.4
		575	0	K23	L211A	1.8	1.9
1.5	1.1	200	0	K42	L750A	6.3	6.8
		230	0	K39	L680A	5.5	5.9
		380	0	K32	L420A	3.3	3.6
		460	0	K29	L343A	2.8	3
		575	0	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	0	K33	L463A	3.8	4.1
		575	0	K29	L380A	3	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	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	L322B	28.4	30.5
		230	1	K67	L293B	24.6	26.4
		380	1	K58	L181B	14.9	16
		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
		460	1	K60	L199B	16.1	17.3
		575	1	K56	L165B	12.9	13.6
15	11	380	2 (1)	K70	L322B	29	31.2
		460	2 (1)	K67	L265B	24	25.8
		575	2 (1)	K62	L220B	19.3	20.7