EPMS

Question 1

What components are on the hot battery bus?

Answer 1

MIK switch
Cold refuel panel
HPSM 1/2 CONT

Question 2

Battery description

Answer 2

FNC
20 cells
12 min at 80%
24 Vdc 15 Amp

Question 3

Battery components

Answer 3

Internal heater (-40 C operations / on at -10 rdy in 30min)
Heater temp sensor (overtemp protection)
Battery temp sensor (signal to charger / control rate of recharge)

Question 4

When does GCU under frequency protection start?

Answer 4

Ground 365 - 380 Hz (2+/-1 sec)

Air 306 Hz (75% RPM)

Question 5

When does GCU over current protection start?

Answer 5

235 amps +/-5 CCR is opened in 5-7 secs

Question 6

What are the GCU protections?

Answer 6

Over voltage
Under voltage
Over current
Under frequency
Feeder fault

Question 7

What does HPSM1 supply power to?

Answer 7

ELC1, CBP1, ECS1, FCR

Question 8

What does HPSM2 supply power to?

Answer 8

ELC2, CBP2, ECS2, Control logic for battery charger

Question 9

ELC components?

Answer 9

68020 processor board
2 I/O modules
3 SP controlled relays modules (mux fails - last commanded position)
PSU1 DC 5+-15 Vdc
PSU2 26 Vac ABC ref for FMC, SP1/2, WP1/2 StabSyncros, 10 Vac for ENG1/2 oil psi transducer and xmsn transducers, 10 Vdc for VCP and BPIA

Question 10

Where is the external power module?

Answer 10

Behind the LMP

Question 11

Where is the CB for external power (EXT PWR INTLK)?

Answer 11

Next to LMP

Question 12

Where does GCU DC backup power come from?

Answer 12

GCU1 - CBP2 | GCU2 CPB1

Question 13

When can you not do an EPMS IBIT?

Answer 13

Airborne
ENG start or override
APU start or stop
Manual generator trip
Fuel boost operation
Zeroize operation
XFEED operation

Question 14

Battery only operations?

Answer 14

WBP1 + 2 are HPSM bus bars (hot)
HPSM1 = KBP01 (Cold Refuel) KBP02 (MIK) KBP10 (SP1 power)
HPSM2 = KBP10 (SP2 power)
KB101/201 (30amps) prevent the battery from powering HPSM until MIK in BATT
When HPSM is powered KB103/203 (50 amps) provide power to CBP1/2
KB102/202 (30 amps) provide 28 Vdc to WB3/4 in ELC1/2 design to trip in overcurrent condition
KD1D1 and KD2D1 block voltage to WD1 and WD2

Question 15

Battery Bus nomenclature?

Answer 15

WB1 + WB2 = HSPM1/2 Bus
WB3 + WB4 = ELC1/2 Bus
WB5 + WB6 = CBP1/2 Bus

Question 16

What does the battery charger do?

Answer 16

Maintains battery in charged state

Provides faults to SP

Question 17

MIK to BATT does what?

Answer 17

KB101/102 close - WB1/2 powered (HPSMs)
KB102/202 close - WB3/WB4 powered (ELCs)
KD1D1/D2 block power to DC bus