2-
2
DIAC Type 66K Digital Overcurrent Relay
GE Power Management
2 PRODUCT DESCRIPTION
GEK-106261
2
2.3 RATINGS
2.4 TOC FUNCTIONS
The TOC function operates on an ‘RMS’ current calculated from the sampled values. The IOC function oper-
ates on the sampled values, and the algorithm virtually eliminates the decaying DC offset component to
achieve low transient overreach of less than 7%.
The relays contain two independent settings: one for TOC and one for IOC. These two settings control the
TOC/Instantaneous function of Stud 10. The TOC/Instantaneous units operate in series with each other as in
the Application Diagram shown in Figure 5–3: TYPICAL EXTERNAL CONNNECTIONS FOR MOTOR PRO-
TECTION on page 5–4.
The TOC function provides 16 selectable time current curves:
The IAC51, IAC53, and IAC77 curves match the time current curve of the respective IAC model. This includes
the 0.5 through 9.9 time dial setting for the 1 and 5 A units. Numbered curves 55, 57, 66, 75, and 95 match the
shape of the respective IAC model; however, the time dial positions are not one-to-one equivalents. The IEC,
IEEE, and I
2
t curves are based on the equations listed with the corresponding curves on pages 2–11 to 2–18.
The I
2
t curve has a K value equal to the time dial times 250. The minimum value of K is 25 (0.1
×
250) and the
maximum value is 2475 (9.9
×
250).
NOTE: IEC equations are defined by IEC 255-4 and IEEE equations are defined by IEEE PC37.112
Table 2–2: RATINGS OF TARGET AND SEAL-IN COIL
CURRENT
OPERATED
UNITS
DUAL-RATED AMP
0.2 AMP TAP
2.0 AMP TAP
Carry 30 amps for
(seconds)
0.05
2.2
Carry 10 amps for
(seconds)
0.45
2.0
Carry continuously
(amperes)
0.37
2.3
Minimum operating
(amperes)
0.2
2.0
Minimum dropout
(amperes)
0.05
0.5
DC resistance
(ohms)
8.3
0.24
60 hertz impedance
(ohms)
50
0.65
50 hertz impedance
(ohms)
42
0.54
•
IAC51
•
IEC Inverse
•
IAC53
•
IEC Very Inverse
•
55-SHORT TIME
•
IEC Extremely Inverse
•
57-MEDIUM TIME
•
IEEE Inverse
•
66-LONG TIME (DIAC Type 66K)
•
IEEE Very Inverse
•
75-SHORT TIME
•
IEEE Extremely Inverse
•
IAC77
•
Definite Time
•
95-SHORT TIME
•
I
2
T
Summary of Contents for DIAC 66K
Page 2: ......
Page 4: ......
Page 54: ...A 2 DIAC Type 66K Digital Overcurrent Relay GE Power Management A 1 CHANGE NOTES APPENDIXA A ...
Page 57: ...GE Power Management DIAC Type 66K Digital Overcurrent Relay NOTES ...
Page 59: ...GE Power Management DIAC Type 66K Digital Overcurrent Relay NOTES ...