In a vehicle equipped with air brakes, what does the governor control?
- When air is pumped into the tanks ✓
- The speed of the air compressor
- The air pressure applied in braking
- When air is released from the brake chambers
Answer: A. When air is pumped into the tanks
The governor controls when air is pumped into the tanks.
Why this is the answer
The handbook says the compressor takes in air from the atmosphere, compresses it, and pumps it into a supply reservoir. It also says the governor must cause the compressor to cut in before pressure falls below 80 p.s.i. That links the governor to switching the compressor on at a set pressure, so it controls when air is pumped into the tanks. The passages do not describe it as setting compressor speed, braking pressure, or the release of air from brake chambers.
Why the other answers are wrong
- B. The speed of the air compressor — The passages describe the governor causing the compressor to cut in, not changing the compressor's speed.
- C. The air pressure applied in braking — The pressure applied during braking is not attributed to the governor in the passages; they tie the governor to compressor cut-in.
- D. When air is released from the brake chambers — Releasing air from the brake chambers is not a governor function in the passages; they mention the governor only in connection with the compressor cutting in.
Remember it
Think of the governor as the switch that tells the compressor when to start filling the tanks.