Heaters
Heaters are not included with the overload relay and must be
ordered separately per the heater selection table and the Information
listed below. When installing heaters be sure that connecting
surfaces are clean and heaters are attached securely to the relay
in the proper location with the screws provided. The trip rating of a
heater in a 40oC Ambient is 125% of the minimum full load current
shown in
Table 5 or 6
. When tested at 600 percent of its trip rating,
the relay will trip in 20 seconds or less (class 20).
The heaters should be selected on the basis of the actual full load
current and service factor as shown on the motor nameplate or in
the manufacturer’s published literature. When the service factor of
the motor is 1.15 to 1.25, select heaters from the heater application
table. If the service factor of the motor is 1.0, or there is no service
factor shown, or a maximum of 115% protection is desired, select
one size smaller heater than indicated. When motor and overload
relay are in different ambient and when using non-compensated
overload relays, select heaters from the table using adjusted motor
currents as follows: decrease rated motor current 1% for each oC
motor ambient exceeds controller ambient. Increase rated motor
current 1 % for each oC controller ambient exceeds motor ambient.
For ambient compensated overload relays no adjustment in heater
selection is necessary for normal variations in ambient temperatures.
Short Circuit Protection
The relay will provide protection against abnormal load conditions to
current values exceeding normal locked rotor current; however, to
protect the relay from short circuit currents, branch circuit protection
must be provided per the National Electric Code. Protective device
ratings should not exceed the maximum values listed in the heater
application table. The relays, as protected are suitable for use on a
circuit capable of delivering not more than 5000 rms symmetrical
amperes.
Maintenance
Other than the normal tightening of all wire and heater connections,
no maintenance should be attempted on the unit. Complete replace-
ment of the unit must be made in the event of damage.
Medium-Voltage applications
The Type A OLR is used with current transformers and the "G" family
of heaters for coordination with mediumvoltage fuses. Since the
current transformers have a limited current output under short-circuit
conditions, no shortcircuit protection is required in their secondary
circuits supplying current to the Type "G" heaters. Wire the second-
ary circuits of the current transformers with #12 or #14 conductors.
Divide the motor full-load current by the transformer turns ratio to
determine the equivalent motor fullload current and select the appro-
priate heater from
Table 5
for a service factor 1.15 medium-voltage
motor.
Table 5. Type G heaters
Code
Marking
Heater Rating
Equivalent
Full-Load Current
G22
G23
G24
G25
G26
G27
G28
G29
G30
G31
G32
G33
G34
2.03A
2.23A
2.44A
2.69A
2.95A
3.23A
3.55A
3.90A
4.28A
4.67A
5.10A
5.50A
6.10A
1.63-1.78 Amperes
1.79-1.95 Amperes
1.96-2.15 Amperes
2.16-2.35 Amperes
2.36-2.58 Amperes
2.59-2.83 Amperes
2.84-3.11 Amperes
3.12-3.42 Amperes
3.43-3.73 Amperes
3.74-4.07 Amperes
4.08-4.39 Amperes
4.40-4.87 Amperes
4.88-5.30 Amperes
Table 6. F series heater selection
For compensated OLR’s in any size enclosure, and non-compensated OLR’s in
enclosures with volume not less than 5500 cu. in. Wire with 75
o
C wire.
For use on one pole OLR’s
Code
Marking
Full Load Current of Motor
(Amperes) (40
o
C Ambient)
Max. Protect.
Device
(Amp)
Load
Wire
Size
FH03
FH04
FH05
FH06
FH07
FH08
FH09
FH10
FH11
FH12
FH13
FH14
FH15
FH16
FH17
FH18
FH19
FH20
FH21
FH22
FH23
FH24
FH25
FH26
FH27
FH28
FH29
FH30
FH31
FH32
FH33
FH34
FH35
FH36
FH37
FH38
FH39
FH40
FH41
FH42
FH43
FH44
FH45
FH46
FH47
FH48
FH49
FH50
FH51
.25 - .27
.28 - .31
.32 - .34
.35 - .38
.39 - .42
.43 - .46
.47 - .50
.51 - .55
.56 - .62
.63 - .68
.69 - .75
.76 - .83
.84 - .91
.92 - 1.00
1.01 - 1.11
1.12 - 1.22
1.23 - 1.34
1.35 - 1.47
1.48 - 1.62
1.63 - 1.78
1.79 - 1.95
1.96 - 2.15
2.16 - 2.35
2.36 - 2.58
2.59 - 2.83
2.84 - 3.11
3.12 - 3.42
3.43 - 3.73
3.74 - 4.07
4.08 - 4.39
4.40 - 4.87
4.88 - 5.3
5.4 - 5.9
6.0 - 6.4
6.5 - 7.1
7.2 - 7.8
7.9 - 8.5
8.6 - 9.4
9.5 - 10.3
10.4 - 11.3
11.4 - 12.4
12.5 - 13.5
13.6 - 14.9
15.0 - 16.3
16.4 - 18.0
18.1 - 19.8
19.9 - 21.7
21.8 - 23.9
24.0 - 26.2
1A
1A
1A
1A
1A
2A
2A
2A
3A
3A
3A
3A
3A
3A
3A
3A
5A
6A
6A
6A
6A
6A
10A
10A
10A
15A
15A
15A
15A
15A
15A
20A
20A
20A
25A
25A
30A
30A
35A
35A
40A
45A
45A
50A
60A
60A
70A
80A
80A
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#14
#12
#12
#12
#10
#10
#10
Above heaters for use on size 1
FH52
FH53
FH54
FHSS
FH56
FH57
26.3 - 28.7
28.8 - 31.4
31.5 - 34.5
34.6 - 37.9
38.0 - 41.5
41.6 - 45.0
90
100
125
125
125
150
#8
#8
#8
#8
#6
#6
Above heaters for use on size 2
m
WARNING:
TO PROVIDE CONTINUED PROTECTION AGAINST FIRE AND SHOCK HAZ-
ARD, THE COMPLETE OVERLOAD RELAY MUST BE REPLACED IF BURNOUT
OF A CURRENT ELEMENT OCCURS. SEE TABLE I.
3
Instruction Leaflet
IL14568
Effective June 2020
Size 1 or 2 Type A Thermal Overload Relay, 3 Pole,
Ambient Compensated or Non-Compensated
EATON
www.eaton.com
