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RANGE
0. 5
- 4.0
0
NOTE:
The impedance values given are those for the minimum tap of each relay.
taps at pick-up current (tap rating) varies inversely (approximately) as the square of the tap rating.
example, for a relay with 0. 5 - 4. 0 amp range, the imQedance of the 0.5 amp tap is given as 1.60 ohms.
impedance of the 2. 0 amp tap at 2.0 amperes is (.5 /2) 2 X 1.6 or 0.10 ohm.
The instantaneous unit burdens are listed in Table IX.
RANGE
60 HZ RELAYS
ONLY (AMPS)
0
0.5-4. 0
2. 0-16. 0
10.0-80. 0
20.0-160. 0
* Low means two windings connected in series.
High means two windings connected in parallel.
See Internal Connections diagram for additional information.
Pick-up of these relays is defined as the current required to close the contacts from the 0.5 time
dial position.
The setting of the time dial determines the length of time the unit requires to close its contacts
when the current reaches the predetermined value.
at zero.
When the dial is set at 10, the disk must travel the maximum distance to close the contacts;
this gives the maximum time setting.
Figure 9 shows the 50 Hl and Figure 10 shows the 60 H� Time Current Characteristics for Relay types
IAC77 and IAC78.
approximately 57 seconds.
The time current curve for the instantaneous unit is shown on Figure 8.
0
These relays, when not included as a part of a control panel, will be shipped in cartons designed to
otect them against damage.
HZ
MIN.
TAP
0. 5
15. 0
60
MIN.
MIN. PICKU P
CONNEC-
TIONS
TAP
*
AMPS
R
OHMS
LOW
0. 5
12. 7
HIGH
3. 18
1.0
LOW
2. 0
0.76
HIGH
4.0
0. 189 0. 180
o.
LOW
1
0
0.042 0. 029 0.051
HIGH
20.0
0. 010 0.007 0.013
LOW
20.0
0.015 0. 008 0.017
HIGH
40.0
0.004 0.002 0.004
The pick -up value in the IAC77 relays is within 3% of the tap value.
The unit resets at 85% of the minimum closing value of current.
The time to reset to the 10 time dial position when the current is reduced to zero is
RECEIVING, HANDLING AND STO RAGE
Immediately upon receipt of a relay, examine it for any damage sustained in
GE K- 3 40 55
TABLE VIII
BU RDENS AT MIN.
PICKUP MIN. TAP
3
z
R
J x
TIMES
PICKUP PICKUP PICKU P
0. 80
1.60
1.60
1. 38
0.085
0.10
TABLE IX
BU RDENS AT
IN OHMS (Z)
3
z
J X
TIMES
OHMS
OHMS
PICKU P
11. 5
17.1
9.6
2. 40
2. 87
4. 28
0. 72
1. 05
0. 59
0.261
0. 147
0. 029
0. 007
0. 010
0. 002
CHARACTER! STI CS
The contacts are just closed when the dial is set
7
BU RDENS IN
V. A. AT 5 AMPS
OHMS (Z)
CALCULATED FROM
IMPEDANCE AT MIN .
PICKU P ( I
10
TIMES
TIMES
1. 60
1. 60
0.17
('). 10
0.10
The impedance for other
BU RDENS
VA AT 5 AMPS
10
20
CALCULATED F ROM
TIMES
TIMES
IM PEDANCE AT MIN.
PICK-U P (I 2
PICKU P
PICKU P
8.7
8. 2
427.5
2. 18
2. 04
107.0
0.53
0.50
0. 133
0. 125
0.026
0.024
0.007
0.006
0.009
0.008
0.002
0. 002
...,. _ ..
· -- ·---:-------------·�------
�)
2
40
For
Th e
z
)
26. 25
6.63
1. 28
0. 33
0.43
0. 10
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