Learjet 35 PTM Chapter 2 (Electrical) Flashcards
The generators are rated for __ Volts and ___ Amps
30 V, 400 A
The Emergency battery can operate what three things?
Stand by attitude Gyro
The landing gear
The flaps
How long can the main batteries power the minimum equipment for night instrument flight?
30 min
What is connected to the L BAT BUS?
L STALL WARN
LIGHTS (Step Lights, Door Lights, Cockpit lighting, Baggage, and Tailcone lighting)
DOOR ACTR Motor
What is connected to the R BAT BUS?
R STALL WARN
Each battery connects to its respective battery hot-bus through a __ Amp current limiter.
20 Amp current limiter
(This protects the hot wired items - stall warning, lights, door actr)
The DC voltmeter is connected to what?
Battery charging bus through a 5 Amp current limiter
Generator voltage is regulated to ____ VDC for lead acid batteries
28.8 VDC
What does depressing the generator reset button do?
It resets the overvoltage relay, and completes a power circuit to the voltage regulator. This resets the generator.
At least one battery switch must be turned on to close the GPU control relay. If the voltage is below ___ V, The power relay closes to complete a GPU-to-battery charging bus connection.
33 V
If GPU voltage exceeds 33 V, the overvoltage circuit causes the power relay to open, thereby disconnecting the GPU from the electrical system to prevent damage to voltage sensitive equipment. Can this be reset?
No, it needs to be sent to Learjet for Replacement.
The AFM recommends that a GPU be used for engine start when ambient temperatures is __°C or below.
0°C
There are two types of current limiters. The lower amperage and higher amperage. How do you tell the difference?
The lower amperage (<50 A) are red and have a pin that protrudes if blown
The higher amperage are made of a gray ceramic material with a small window that allows visual inspection.
What will our situation become if both 275 Amp current limiters fail in flight?
The batteries are no longer being charged by the battery charging bus. Our DC Volt meter will read battery voltage. We have about 30 minutes before our main batteries are depleted and we switch over to emergency battery power.
Immediately find and remain in VMC, declare an emergency, run the respective checklists, land as soon as possible!
What purpose do relays serve?
They allow the control circuit wiring to be a lighter gauge since less current is required to operate the relay… vs. what is the alternative?
On FC – 200 AFCS aircraft where are the additional auto pilot circuit breakers?
Under the pilot seat on the auto pilot electric box
The DC circuit breakers are the ________ type, and the AC circuit breakers are the ________ type.
DC - Thermal
AC - Magnetic
If you unplug the GPU or both generators fail, will the Freon AC or auxiliary heater turn off?
No! It is the pilot’s responsibility to turn those off to preserve battery life.
What are the numbers on each circuit breaker?
Amperage ratings
Where are the inverters located in the aircraft?
The tail cone
If you have an auxiliary inverter, when should it be operated?
It is recommended that it be operated all the time in conjunction with the primary and secondary inverters in order to extend inverter life.
What is the voltage output of the inverters?
115 VAC
A __________ takes 115 VAC and steps it down to 26 VAC for some instruments and avionics.
Transformer
The PRI Inverter current goes to the ____ BUS, which means the SEC Inverter powers the ____ BUS.
PRI - Left BUS
SEC - Right BUS
This is important to understand because if your aircraft has an auxiliary inverter, we need to know which BUS to send power to if an inverter fails.
When we turn on the emergency battery during the cockpit check, the small amber EMR PWR light comes on. Why does this come on?
The EMR PWR lights illuminates when the emergency battery is NOT being charged. (When it is discharging). If this light comes on at any time in flight, It means the normal electrical system has failed.
It is recommended to place the switch to standby until gear or flap operation is required in order to conserve battery life
What is powered when the EMER PWR switch is ON?
Stand by attitude indicator and back lighting.
Landing gear control circuits and green position lights.
Flap control circuits, but not flap indicator.
RVSM Pilot altimeter.
STBY Altimeter Vibrator.
What is a standby altimeter vibrator?
It is a vibrator that shakes to reduce friction errors and to prevent the indicator from sticking!
Battery life for the Emergency BATT is ________ on STBY, and ________ in the ON position.
3 hrs 45 min on STBY
30 min in the ON position
If there are two emergency batteries, what typically will the second emergency battery power?
At least one radio for communication. It can sometimes also power NAV 1, a transponder, and the TCAS system
Draw out as much of the electrical system as you can. Refer to the PTM 2-22,23
PTM 2-22,23 (Depending on Serial #)
