Title: Quiz 1
Course: Advd Fluid Pwr & Servo Systems (EGT-152-1)(2016SP)

Q: A vehicle has hydraulic motors to drive it down the road, which sensors are appropriate to close the loop to control SPEED?
- Flow meter or Tachometer
- Presssure sensor or LVDT
- Rotary Potentiometer
A: Flow meter or Tachometer

Q: A hydraulic press travels 36.0 inches vertically, 30.0 inches in rapid travel and 6.00 inches in slow feed, what type of sensor is appropriate to close this POSITION  loop?
- LVDT or linear potentiometer
- pressure transducer
- flow meter
- tachometer
A: LVDT or linear potentiometer

Q: The SENSITIVITY of a sensor is:
- output divided by input
- input divided by input
A: output divided by input

Q: A pressure sensor give what as it's output?
- mV, or mA
- psi
- GPM
A: mV, or mA

Q: A flow meter gives what as it's output?
- a frequency, to be rectified to DC
- pure DC
- gpm
- psi
A: a frequency, to be rectified to DC

Q: An engineer says a sensor-transducer needs to produce a Gain of .002mv/psi, what is the term you would look up in the sensor technical specification which means the same thing?
- Sensitivity
- Precision
- Linearity
- Reliability
A: Sensitivity

Q: Term "percent error of full scale" describes what?
- the biggest output error measurable, divided by the highest sensor output rating x 100
- the average variation in tested values divided by the full scale output, x 100
- the maximum error from the mean, divided by the full scale output rating of the sensor, x 100
A: the biggest output error measurable, divided by the highest sensor output rating x 100

Q: A page of the sensor data sheet says " % error of F.S. = +/-1% @ 5000 psi."

What is the maximum psi error allowable EITHER above or below the mean pressure for this sensor if the sensor is fully operating within specifications?
- 50psi
- 5 psi
- .5 psi
- .05psi
A: 50psi

Q: With Excell charting, the y = mX + b formula function creates WHAT in your test data?
- The statistical mean value line extrapolated from all the data points
- a line of some kind
- a line with a slope exactly equal to the sensitivity of the sensor. (great answer, but not quite right.)
A: The statistical mean value line extrapolated from all the data points

Q: A rotary potentiometer is used to control the height of a concrete paver to within 1/8" of the desired string height.  If the whisker attached to the rotating POT axis,is 10" long, where motion of 1/8" rotates the axis and thus rotates the POT wiper, eg. (the Opposite Side is 1/8" and the Adjacent Side is 10"),  Will a rotary pot with a sensitivity of .5mV/1degree, be appropriate to use as a feedback sensor?
- yes
- no
- nobody knows
- I don't know
A: yes

Q: A pressure sensor has a thermal drift of .02mV per C degree at 0 C,  what error in pressure is expected at 180C?
- 3.6 psi
- .36 psi
- .036 psi
A: 3.6 psi

Q: A flow meter data sheet lists sensitivity as 2715Hz / 7.5 GPM, what should the frequency be at 3 GPM?
- 1086 Hz
- 6081 Hz
- 1608 Hz
- 6108 Hz
A: 1086 Hz

Q: From heat discussions at the start of the semester, servo hydraulics waste up to 50% of the HHP delivered to a Load because of the turbulence of fluid making sharp right angle turns inside the valve, manifold, and fittings.  If a load requires 22 HHP net, what Q must be available from the power supply, to if working pressure = 2000 psi? (formula.. P*Q/1714=HHP)?
- 37.7 GPM
- 15.5 GPM
- 44 GPM
A: 37.7 GPM

Q: Op Amps are most often used to power servo valves, in which configuration?
- Inverting input config
- non-inverting config
- comparitor config.
A: Inverting input config

Q: You have witnessed one closed loop positional circuit. Why does the "step input" signal and the "feedback" signal need to be opposite polarities?
- So their voltage sum can be = (0) zero at the summing junction before entering the op amp.
- So you can tell which is which
- So that the polarity of the step input can always be positive voltage
A: So their voltage sum can be = (0) zero at the summing junction before entering the op amp.

Q: A single Op amp chip has + bias voltage and - bias voltage to power it before you input any signal to it.  What is the tuning procedure called when you adjust a potentiometer to precisely make the + bias = - bias ?
- Electrical nulling
- Nulling
- threshold adjustment
- setting the gain
A: Electrical nulling

Q: All flapper nozzle valves and jet pipe valves have a small screw at the top accessible with a 1/16" allen wrench.  What is this screw used for?
- Its used to adjust jet's distance from the flapper to make Pa = Pb.
- to change the minumum flow of the valve
- to correct for small currents coming to the valve coil
- don't need to be tampered with ever.
A: Its used to adjust jet's distance from the flapper to make Pa = Pb.

Q: What response do you expect a machine to show if EITHER the "null screw" or the Bias screw are not nulled at "zero"?
- all of the above/below
- a linear actuator will slowly move to one side and tend to go there uncontrolled
- a motor will tend to rotate when it should be stopped
A: all of the above/below

Q: From your book there are three types of spool lap conditions you can purchase in high performance directional valves, Overlap, Zerolap, and Underlap.  Which is most common.
- Over lap
- Zero lap
- Under lap
A: Over lap

Q: From your book, Chap 3, Equation #1 about , Why doesn't the flow Q double in a circuit when the working pressure P is doubled?
- Because turbulence of fluid entering a round hole, turing a 90 degree angle over a sharp edge port, wastes energy equivalent to the change in presure
- The flow DOES double... trick question
- Because the change in pressure is reversed by the resistance of pressure on both sides of the
A: Because turbulence of fluid entering a round hole, turing a 90 degree angle over a sharp edge port, wastes energy equivalent to the change in presure

Q: Compare Q _ACTUAL to Q_ rated of a system. Which Q is used to select a valve from manufacturer's literature by comparison to other valves?
- Q rated
- Q actual
A: Q rated