Operating Inverter with Front Panel Open

TM 11-6130-377-14

(1)

Position the DC circuit breaker to OFF.

through (3) below to sectionalize the fault in the inverter

to a definite location. The checks are arranged to reduce

(2) Open front panel to gain access to the door

unnecessary work and aid in tracing the fault to the basic

interlock switch plunger located on the right side of the

unit responsible for abnormal operation.

door frame (fig. 2-1).

(1) Visual inspection.

Some faults in the

(3) Grasp the plunger and pull it out until it

inverter can be sectionalized to a specific area by merely

clicks into the extended detent. The system is now ready

observing the operating and nonoperating status of the

for power to be applied and tests can be made.

unit e.g., malfunctioning circuit breakers, damaged wires

b. To apply DC power to the inverter from the Deltec

or cables, etc.

2592 Variable DC Power Source or equivalent (para. 6-2)

(2) Operational checks.

When visual

make the connections to the input terminals A1TB1 of the

inspection fails to sectionalize a fault in the inverter to a

inverter as shown in figure 6-2.

major item, utilize the troubleshooting results contained in

c. To connect the Deltec 2951 Load Bank or

paragraph 4-10 of this manual.

equivalent (para 6-2) to the inverter make the connections

(3) Localization.

After the fault has been

to the output terminals A1TB3 (fig. 6-2).

sectionalized to a major item, it is necessary to localize

6-6. Inverter Troubleshooting Chart

the fault to a group of components or circuits within the

faulty unit.

The localization procedures found in

WARNING

troubleshooting chart (para 6-5b), will aid the repairman in

110 vdc is present in the inverter. Do

localizing faults in the inverter. In some cases the

not remove or replace parts, nor

localization procedures will isolate the fault to a

perform continuity or resistance

replaceable component, wire, or piece part. If not, the

checks while primary power is applied

localization procedure will reference the isolation

to the unit.

procedure to be used.

a. Use of the Chart. To use the chart, read down the

6-5. Operating Inverter with Front Panel Open

Symptom column of the troubleshooting chart until the

If the front panel is opened, the door interlock switch will

abnormal symptom or condition is found. Perform the

cause the inverter to shut down, refer to paragraph 5-

corrective actions indicated in the chart until the abnormal

2b(5) for detailed explanation of switch in circuit.

symptom or condition is corrected. Figures 6-1 and FO-3

are parts location diagrams which will aid the

a. Use the following procedure to override the door

maintenance man in locating designated parts.

interlock switch when it is necessary to test or

troubleshoot the inverter which the front panel is open.

b. Inverter Troubleshooting Chart.

Item

No.

Symptoms

Probable trouble

Corrective Action

Input fuse A1F1 blows when re-

Defective inverter drive A1A2.

Turn circuit breaker A1CB1(FO-1) off

placed or circuit breaker A1CB1

and replace input fuse A1F1 (FO-1) if

trips when reset (1973 model

necessary. Remove connector A1A2J1

(FO-3) from the inverter drive printed

circuit (PC) board and observe the

contacts of relay A1K2 (fig. 6-1) as

circuit breaker A1CB1 (fig. 6-1) is

turned on the second time. A1K2 is the

top relay mounted on the left side of the

heat sink tunnel). If the contacts of

relay A1K1(fig. 6-1) close at turn on, the

problem is probably a defective inverter

drive. Replace inverter drive A1A2 (FO-

3) in its entirety. Refer to paragraphs 6-

8 and 6-9 for repair.

Change 1

6-2