General Electric MicroVersaTrip® RMS-9 Conversion Kit Installation Instructions

Introduction

These instructions cover the installation of the MicroVersaTrip® RMS-9 solid state overcurrent trip device conversion kits on AK-15 and AK-25 frame breakers originally equipped with EC, Power Sensor, or SST type trip devices. Each kit contains the necessary materials to convert any type. The kits are designed specifically for use on the following breakers:

Table 1 - Convertible Breaker Models

*MicroVersaTrip® RMS-9 programmer extends 3/8" beyond breaker's right side outline.

Kit installation is a straightforward operation but requires careful workmanship and attention to these instructions. Familiarity with the breaker itself is highly desirable. The general approach is to first strip the breaker of its existing trip devices (either EC, SST, or Power Sensor), then install the MicroVersaTrip® RMS-9 components. Following this, the converted breaker is performance-tested prior to restoring it to service.

For the majority of breaker models listed in Table 1, kit installation does not require any customized assembly work. However, some conversions may involve unusual mounting circumstances or accessory combinations which necessitate minor modification/relocation of a component(s). In most instances, this supplementary work can be done on site.

Preparatory to beginning the conversion, the installer should verify that the correct kit, current sensors, and programmer unit have been furnished (see Tables 2, 3, and 4). Whenever the ground fault trip element is furnished for breakers applied on 4-wire systems, note that in addition to installing the kit on the breaker, an associated neutral sensor (CT) must be separately mounted in the equipment. Ensure also that retrofitted breakers are applied within their short circuit ratings; for example, as part of a conversion when the breaker's trip elements are to be changed from instantaneous to short time, the short time rating would govern the application.

Tools Required

• Socket Set - 3/8" drive
• Pliers - Assorted
• Open End Wrenches - Set
• Electric Drill
• Screwdrivers - Assorted
• Drill Bits
• Allen Wrenches - Assorted
• 6" Scale
• Tru-arc Pliers - Assorted
• Crimping Tool
• Spring Scale 0-75 lbs.

Users are reminded that the installation of MicroVersaTrip® RMS-9 kits provides an excellent opportunity to perform normal maintenance on the breaker, particularly while the front and back frames are separated. Renewal parts are available as listed in bulletin GEF-4149G, a copy of which is included with each MicroVersaTrip® RMS-9 kit.

Table 2 - MicroVersaTrip® RMS-9 Conversion Kit Model Selection For Tapped Sensor With Fixed Rating Plug

Example: AK-25, Stationary construction, 4-wire system, 600 Amp tapped sensor, LIGT2 programmer. MicroVersaTrip® RMS-9 conversion kit model number: TK025S4T0603 (fixed rating plug will be installed in programmer).

Table 3 - Available Programmer Functions For MicroVersaTrip® RMS-9 Conversion Kits

Table 4 - Tapped Current Sensors For Use With MicroVersaTrip® RMS-9 Conversion Kits

Preparing the Breaker

WARNING: Before starting any work, disconnect the breaker from all power sources (primary and secondary) and place in a clean work area.

1. Remove the steel arc quencher retainer by loosening the two 1/4 x 20 hex capnuts. On electrically operated AK-3/3A-25 breakers, the "Y" relay is mounted on the left end of the retainer, but there is no need to remove it.
2. Remove the three arc quenchers by lifting upward and outward.
3. Separate the breaker's front and back frames. Refer to maintenance manual GEI-50299, page 5; if Power Sensor, see pp. 28-31 also.

4. CAUTION: Be careful to avoid damage to breaker components during this operation.

5. Remove the overcurrent trip devices. Refer to maintenance manual GEI-50299 pp. 23, 31.
6. On draw-out breakers, remove the primary disconnect fingers from the bottom (load-side) copper studs. Refer to maintenance manual GEI-50299, page 7.
7. Remove the three bottom (load-side) copper stud assemblies. On Power Sensor-equipped breakers, this will have been done during Step 4 above.
8. On electrically operated breakers equipped with EC trip devices, the "Y" relay is mounted on the front frame at the right side of the operating mechanism. To provide mounting space for the MicroVersaTrip® RMS-9 flux shift trip device, remove the "Y" relay and remount it on the left end of the arc quencher retainer as shown in Figs. 1 and 2 (using hardware and parts included). Modify the breaker's wiring harness to suit.
9. On EC-equipped breakers, remove and discard the four trip device support brackets mounted along the lower front of the back frame. See Fig. 3. At this point, the breaker back frame is ready for installation of the kit.

Figure 1 shows a front view of the front frame (AKD type draw-out shown), illustrating components such as the "Y" relay location, wire keepers, programmer connector, and magnetic trip device location.

Figure 2 shows a right side view of the front frame, indicating wiring harness modifications for the "Y" relay.

Figure 3 shows a front view of the rear frame, highlighting EC trip support brackets.

Installing the Kit

1. Modify the left and right pole lower stud insulator shields per Fig. 8; remount on back plate using original screws and special nut (item 93 on Fig. 7) supplied with the kit.
2. Assemble and mount the three current sensor (CT) assemblies to the back frame. See Figs. 5, 6, and 7. For each pole, first insert lower copper stud 90 through the back plate and attach it via the mounting screw. Then position CT 18 with its terminals toward the rear and loosely mount it to stud 90 with copper parts 91 and 92. Align the assembly and torque the two 3/8" bolts in strap 91 to 25 ft.-lbs. each to assure proper contact integrity.
3. Install CT terminal board-mounting bracket 80 below the CT's using the (2) 8-32 x 1/2" screws provided. See Fig. 5. Mount terminal boards TB1, TB2, and TB3 to the bracket using the (6) 6-32 x 1/2" screws and washers provided.
4. On draw-out type breakers, remount the primary disconnect fingers on the new lower studs. Refer to maintenance manual GEI-50299, pp. 7 and 13.
5. NOTE: On all AK-15 draw-out breakers, modify primary disconnects per instructions on Page 25.

6. CAUTION: Adequate primary contact force is mandatory. Tighten the nuts on the 1/4 x 20 mounting bolts to obtain a spring dimension of 13/16 to 27/32. The proper dimension between contact fingers is 7/16". Proper contact force is 60 to 70 lbs. with the contacts spread to 1/2".

7. Mount insulator bracket 70 to the lower right corner of the back frame utilizing existing holes. See Fig. 20.
8. Install wire harness 100 on the back frame and connect per instructions on Figs. 9, 12, or 16 as applicable to the particular breaker type involved. For tie-down and forming details, see Fig. 5. This step completes conversion of the back frame (see example illustrated in Fig. 4).
9. Proceeding to the front frame, mount the flux shift trip paddle on the breaker's trip shaft per Figs. 17 and 18.
10. Mount the flux shift trip device per Figs. 17 and 19. NOTE: Adjustment of trip rod length will be performed later in Step 13.
11. On electrical breakers, remove "x" relay and mounting bracket from the front frame. Assemble programmer shock mount bracket (76) to programmer support bracket (71) per Fig. 20. Mount "x" relay on bracket using (3) #10 screws and lock washers provided. Modify the "x" relay harness by adding 16 Ga. extension wire, splices, and ring terminals provided. Work one wire at a time to prevent wiring errors. Route wires as shown in Fig. 21, making certain they do not interfere with the solenoid plunger or programmer. Install bracket assembly per Fig. 20.
12. Referring to Fig. 6, install flux shifter actuating bushing 49 in the right-hand operating link, enlarging the link hole if necessary. See Fig. 4 also.
13. Rejoin the front and back frames. Refer to maintenance manual GEI-50299, Page 5.
14. Connect wire harness "X" (attached to flux shift trip device) to the programmer connector per Table 5. Exercise care in routing to prevent leads being damaged by moving breaker components such as contact assemblies.
15. Adjust flux shift trip rod gap per instructions on Fig. 17.
16. Place harness connector (100) into the programmer shock mount bracket (76). See Fig. 9A. Install the plug adapter (205) onto the harness connector. Refer to Fig. 9A for proper orientation of the plug connector. Place the combination plug adapter/harness connector over the guide pins and slide the assembly down the pins until the slots in the plug adapter align with the retaining tabs in the shock mount bracket. Bend the tabs in the shock mount bracket into the plug adapter to capture the plug assembly on both sides. Check that the "PULL TO UNLOCK" tab is out so that the bracket can accept the programmer. Install the programmer.

17. CAUTION: To avoid shock hazard and possible damage to wire harness and sensor coils, the harness connector must be securely mated with the programmer unit before the breaker is energized.

Conversion of the breaker is now complete. A typical example is shown in Fig. 22. Reassemble arc chutes. Proceed to Section IV - EQUIPMENT MODIFICATIONS. If these are not required, proceed directly to Section V - FUNCTIONAL TESTING.

Figure 4 shows the AK-25 back frame with MicroVersaTrip® RMS-9 conversion components installed and ready for reassembly to the front frame.

Figure 5 shows the back frame assembly, detailing terminal boards (TB1, TB2, TB3, TB5), harness connections, and component mounting.

Figure 6 shows a right side view of the back frame.

Figure 7 shows a right side view of the phase sensor assembly.

Figure 8 illustrates stud insulator modification.

Figure 9 details harness connections for drawout and stationary breakers used on 3-wire systems, with and without ground fault.

Table 5 lists harness connections, specifying components, terminal boards, wire colors, and harness connector pin numbers.

Figure 9A illustrates the connector sub-assembly for the harness connector and programmer support.

Figure 10 provides a cabling diagram for MicroVersaTrip® RMS-9 without ground fault.

Figure 11 provides a cabling diagram for MicroVersaTrip® RMS-9 with ground fault on a 3-wire load.

Figure 12 details harness connections for drawout breakers equipped with 4-wire ground fault.

Figure 13 shows the mounting detail for the secondary disconnect block 120 for the 4th-wire neutral sensor (draw-out breakers only).

Figure 14 provides a cabling diagram for MicroVersaTrip® RMS-9 with ground fault on a 4-wire load for a draw-out breaker.

Figure 15 provides a cabling diagram for MicroVersaTrip® RMS-9 with ground fault on a 4-wire load for a stationary breaker.

Figure 16 details harness connections for stationary breakers equipped with 4-wire ground fault.

Figure 17 shows a right side view of the mechanism frame illustrating the mounting of the flux shift trip device 40. It also provides instructions for adjusting the flux shift trip rod gap and mounting the device on different breaker types.

Figure 18 shows a rear view of the front frame indicating the location of the trip paddle for the flux shift trip device.

Figure 19 shows a right side view of the operating mechanism illustrating the mounting of the flux shift trip device.

Figure 20 shows a right side view of the breaker illustrating the mounting of the programmer unit, including "X" relay location and harness routing.

Figure 21 shows the "X" Relay location with harness routing.

Equipment Modifications

NOTE: The following modifications are required ONLY in conjunction with breakers being equipped with 4-wire Ground Fault trip elements.

1. Mount the neutral sensor (CT) in the outgoing neutral lead, normally in the equipment's bus or cable compartment. See Fig. 22 for the sensor's bar drilling plan. Check to ensure that the neutral and phase sensors match, i.e., have the same ampere range.
2. On draw-out-type breakers, mount the 4th-wire neutral sensor stationary disconnect block 121 inside the breaker compartment at the lower rear as shown in Figs. 23 or 24, whichever applies. For the AKD-5-type equipments of Fig. 24, be careful to select the correct mounting bracket (Part 126 or 127).
3. Connect the neutral sensor to disconnect block 121 per wiring instructions of Fig. 25. For stationary breakers, the neutral sensor is connected to TB5.

Figure 22 outlines the MicroVersaTrip® RMS-9 Neutral Sensors, listing Cat. TSVG225BK (70-225 amp) and Cat. TSVG206BK (200-600 amp).

Figure 23 illustrates the mounting of the 4th-wire neutral sensor disconnect block in AKD-5 switchgear compartments and AKD-5 type OEM boxes.

Figure 24 illustrates the mounting of the 4th-wire neutral sensor disconnect block in AKD type OEM box.

Figure 25 details connecting the 4th-wire neutral sensor, including notes on line and load markings, polarity, and bonding.

Functional Testing

Before the breaker is reinstalled to service:

1. Megger breaker primary circuit using a 1000V megger. Any value exceeding 500 megohm is acceptable.
2. Perform either of the following tests:
   • A - Using MicroVersaTrip® RMS-9 portable test set Catalog TVRMS, test per instructions GEK-97367 to assure proper operation of the breaker and its trip device.
   • B - Using a single-phase, high current-low voltage test set, test each trip element (L, S, I, G) to assure proper protective device operation. Compare results with applicable time-current characteristic curves reproduced on pages 25 and 26.

3. NOTE: When testing units equipped with a ground fault trip element, the latter must be deactivated by using test set Cat. No. TVRMS. If a high current test set (primary injection) is being used, and portable test set TVRMS is not available, connect two poles in series. MicroVersaTrip ground fault defeat cable Cat. No. TVTGD9 CANNOT and MUST NOT be used to temporarily defeat the MicroVersaTrip® RMS-9 programmer ground fault function. Programmer damage may result.

Pages 25 and 26 contain time-current characteristic curves for Low-Voltage Power Circuit Breakers, Type AKR, with MicroVersaTrip® RMS-9 or Epic MicroVersaTrip™ for various trip functions (Long-time, Short-time, Instantaneous, and Ground Fault).

AK-2/3-15 Reassembly of Primary Disconnects for New Lower Stud - Draw-Out Breakers

1. Place spacer with off-center hole (162) in hole of stud while sliding new retainer (161) completely on stud.
2. Place new retaining ring (163) on stud. Insert lip of upper fingers under retaining ring and place bow tie spacers in fingers.
3. Place retainer over upper fingers and insert bolt.
4. Insert lip of lower fingers under retaining ring (163) and place bow tie-shaped spacers in fingers. Locate lower retainer to hold bow tie-shaped spacers in place.
5. Place cylindrical spacer and spring on bolt and secure with washer and nut.
6. Tighten nut to obtain 60-70 lbs. pressure per set of four fingers when spread 1/2" apart, as shown, and lock with second nut.

Note: If pressure gauge not available, compress spring to a 13/16" dimension for proper pressure.