GE MI-869 User Manual

CHAPTER 2: INSTALLATION ELECTRICAL INSTALLATION
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL 2–17
Wire Size Use the following guideline when selecting wires or lugs to connect to terminal strips A, B,
C, D, E, F, G, H, and terminal blocks J, K. Note that the first two bullets are applicable to
terminal blocks J and K only:
• 12 AWG to 22 AWG (3.3 mm
2
to 0.3 mm
2
): Single wire termination with/without 9.53
mm (0.375”) maximum diameter ring terminals.
• 14 AWG to 22 AWG (2.1 mm
2
to 0.3 mm
2
): Multiple wire termination with 9.53 mm
(0.375”) maximum diameter ring terminals. Two ring terminals maximum per circuit.
• Suggested wiring screw tightening torques are: terminal strips A-H tighten to 4.5 in-lbs
(0.5 N-m) and t
erminal blocks J, K to 15 in-lb (1.7 N-m).
Figure 2-18: Fiber Connector Types (S - ST)
Phase Sequence and Transformer Polarity
For correct operation of the relay features, follow the instrument transformer polarities,
shown in the Typical Wiring Diagram above. Note the solid square markings that are
shown with all instrument transformer connections. When the connections adhere to the
drawing, the arrow shows the direction of power flow for positive watts and the positive
direction of lagging vars. The phase sequence is user programmable for either ABC or ACB
rotation.
The 869 relay has four (4) current inputs in each J slot and K slot. Three of them are used
for c
onnecting to the phase CT phases A, B, and C. The fourth input is a ground input that
can be connected to either a ground CT placed on the neutral from a Wye connected
transformer winding, or to a “donut” type CT measuring feeder ground fault current.
869 relay CT inputs are grouped into terminal block assembly, mounted on the rear of the
chas
sis. There are no internal ground connections on the current inputs. Current
transformers with 1 to 12000 A primaries may be used.
CAUTION:
Verify that the relay’s nominal input current of 1 A or 5 A matches the secondary rating
of the connected CTs. Unmatched CTs may result in equipment damage or inadequate
protection.
CAUTION:
IMPORTANT: The phase and ground current inputs correctly measure up to 46 times the
current input’s nominal rating. Time overcurrent curves become horizontal lines for
currents above 20 × PKP.

GE MI-869 Specifications

General

Brand	GE
Model	MI-869
Category	Protection Device
Language	English