Current Ramping I (Fuel Pumps) quiz


1	When using a low current probe set at 100mV = 1 amp, what time base and voltage scale should most commonly be used to set up your scope for viewing fuel pump waveforms ?
		10 mV/div & 20 ms/div
		100V/div & 2s/div
		1 mV/div & 200ms/div
		100mV/div & 2ms/div


2	Although most domestic fuel pump motors use 8 bar commutators, how can you determine the actual number of commutator bars from the amperage waveform?
		Count the total number of humps visible on the scope screen.
		Look for repetitive, matching "humps" which represent the same bar and count the bars in between.
		You can only determine the number of bars by cutting the fuel pump motor apart.
		The number of amps = The number of commutator bars


3	The time for 1 pump revolution is divided into what number when calculating the pump motor speed?
		60
		6000
		60000
		600000


4	Which brush usually fails first in a fuel pump motor?
		The positive brush.
		The negative brush.
		Both positive and negative brushes fail at the same time.
		Brush failure never occurs in fuel pump motors.


5	Technician A states that higher fuel pressure at the injector(s) equals higher fuel pump current draw. Technician B states that a restricted fuel filter will cause higher than normal fuel pump current draw. Who is correct?
		Technician A
		Technician B
		Both Technician A & B
		Neither Technician A or B