OVERLOAD PROTECTION OF THREE
PHASE SUBMERSIBLE MOTORS –
CLASS 10 PROTECTION REQUIRED
The characteristics of submersible motors are
different from standard motors and special overload protection is required.
If the motor is stalled, the overload protector
must trip within 10 seconds to protect the motor
windings. The installer must use SUBTROL or
the quick-trip protection shown in these tables.
All recommended overload selections are of the
ambient compensated type to maintain protection at high and low air temperatures.
All heaters and amp settings shown are based
on total line amps. When a six-lead motor is
used with a Wye-Delta starter, divide motor
amps by 1.732 to make your selection or adjustment for heaters carrying phase amps.
Table I lists the correct selection and settings for
several manufacturers. Approval of other types
may be requsted from the motor manufacturer.
NOTICE: Warranty on three phase submersible
motors is void unless proper quick trip protection in all three motor lines is used.
FOOTNOTES:
NOTE 1: Furnas intermediate sizes between NEMA
starter sizes apply where (1) is shown in tables, size 13/4 replacing 2, 2-1/2 replacing 3, 3-1/2 replacing 4
and 4-1/2 replacing 5. Heaters were selected from
Catalog 294, Table 332 and Table 632 (starter size 00,
size B). Size 4 starters are heater type 4 (JG). Starters
using these heater tables include classes 14, 17 and 18
(INNOVA), classes 36 and 37 (reduced voltage), and
classes 87, 88 and 89 (pump and motor control centers). Overload relay adjustments should be set no
higher than 100% unless necessary to stop nuisance
tripping with measured amps in all lines below nameplate maximum. Heater selections for class 16 starters
(Magnetic Definite Purpose) will be furnished upon
request.
NOTE 2: Allen-Bradley heaters were selected from
Catalog IC-110, Table 162 (through starter size 4), Table
547 (starter size 5), and Table 196 (starter size 6).
Bulletin 505, 509, 520, 540 and 570 use these heater
tables. Heater selections for bulletin 1232X and 1233X
starters will be furnished upon request.
NOTE 3: General Electric heaters are type CR123
usable only on type CR124 overload relays and were
selected from Catalog GEP-126OJ, page 184.
Adjustment should be set no higher than 100%, unless
necessary to stop nuisance tripping with measured
amps in all lines below nameplate maximum.
NOTE 4: Adjustable overload relay amp settings apply
to approved types listed. Relay adjustment should be
set at the specified SET amps. Only if tripping occurs
with amps in all lines measured to be within nameplate
maximum amps should the setting be increased, not to
exceed the MAX value shown.
RECOMMENDED ADJUSTABLE
OVERLOAD RELAYS
AEG Series: B17S, B27S, B27-2.
Allen Bradley: Bulletin 193, SMP-Class 10 only.
Fanal Types: K7 or K7D through K400.
Franklin Electric: Subtrol-Plus.
General Electric: CR4G, CR7G, RT*1, RT*2, RTF3, RT*4,
CR324X-Class 10 only.
Klockner-Moeller Types: Z00, Z1, Z4, PKZM1, PKZM3, PKZ2.
Lovato: RC9, RC22, RC80, RF9, RF25, RF95.
Siemens Types: 3UA50, -52, -54, -55, -58, -59, -60, -61, -62,
-66, -68, -70, 3VUI3, 3VE, 3UB (Class 5).
Sprecher and Schuh Types: CT, CT1, CTA 1, CT3K, CT3-12
thru CT3-42, KTA3, CEF1 & CET3 set at 6 sec. max., CEP 7
Class 10, CT4, 6, & 7, CT3.
Square D/Telemecanique: Class 9065 types TD, TE, TF, TG,
TJ, TK, TR, TJE, TJF (Class 10) or LR1-D, LR1-F, LR2-D13,
-D23, -D33, Types 18A, 32A, SS-Class 10, SR-Class 10 and
63-A-LB Series. Integral 18,32,63, GV2-L, GV2-M, GV2-P,
GV3-M (1.6-10 amp only).
Westinghouse Types: FT13, FT23, FT33, FT43, K7D, K27D,
K67D, Advantage (Class 10), MOR, IQ500 (Class 5).
Other relay types from these and other manufacturers
may or may not provide acceptable protection, and
they should not be used without approval of Franklin
Electric.
Some approved types may only be available for part of
the listed motor ratings. When relays are used with current transformers, relay setting is the specified amps
divided by the transformer ratio.
SURGE ARRESTERS IN CONTROL BOX
Grounding: When the box has a surge arrester,
it MUST be grounded, metal to metal, all the
way to the water strata for the arrester to be
effective. Grounding the arrester to a driven
ground rod provides little or no protection for
the motor.
NOTICE: Surge arresters DO NOT protect
against direct lightning strikes.
Install grounded surge arresters to protect pump
from high voltage surges. Install arrester on the
incoming power line to control box or pressure
switch, as close to pump motor as possible. See
Figures 1 and 2 for installation wiring diagrams
for arresters.
NOTICE: Ground the arrester with a No. 10 or
larger bare wire. Ground according to local
code requirements.
NOTICE: If surge arresters wired into the control
box are against local electrical code, contact
power company for correct wiring information.
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