Motor Controls: Timers

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  1. Functions and techniques divide industrial timers into how many categories? What are they? NJATC, Motor Controls: timers, 2010 PP 127
    Dashpot controlled, synchronous clock, and solid-state.
  2. Which is more accurate a mechanical timing relay or an electronic timing relay? NJATC, Motor Controls: timers, 2010, PP 128
    An electronic timing relay is more accurate
  3. The timer functions available from most suppliers include What? NJATC, Motor Controls: timers, 2010, PP 128
    On delay, off delay, one-shot, fleeting off delay, repeat cycle (or flasher) are all of these.
  4. The two most common functions used by a timer are what? NJATC, Motor Controls: timers, 2010, PP 128
    On delay and off delay are the most common functions used by this.
  5. On delay timers have no, or some, change during the timing with the output contacts.
    On delay have no change and start out timing when the contacts are energized.  The memory method is ON DELAY=NOTC NCTO, whereas off delay is NOTO and NCTC.
  6. On delay timers are also called what? NJATC, Motor Controls: timers, 2010, PP 129
    Delay on energize or DOE.  They start timing when energy is applied and change state at the end of timing.
  7. What type of timer is a device with a preset time. That starts after the input signal is removed from electronic timing relay or power is removed from a mechanical timing relay? NJATC, Motor Controls: timers, 2010, PP 129
    This describes an OFF DELAY timer.
  8. The timed contacts of the timer immediately change state when the timer is energized or initialized and returned to their original state after the set time delay has elapsed describes what type of timer? NJATC, Motor Controls: timers, 2010, PP130
    Off delay timer also known as DODE.  Think NO(TO) and NC(TC) where ( ) is the end of timing sequence, meaning the contacts changed when the power was removed from the timer.
  9. Components drawn on motor control drawings are in their what state? NJATC, Motor Controls: timers, 2010, PP 130
    • These components are in the deenergized or on the shelf state, also called the normal state.
  10. Associate on delay with the delay starting when timers are turned on, or energized. Associate off delay with? NJATC, Motor Controls: timers, 2010, PP 132
    when the mechanical timers are turned off or deenergized. Removal of the trigger or power starts the delay time.
  11. The arrow points up or down when depicting on or off delay and how do you remember this? NJATC, Motor Controls: timers, 2010, PP 132
    The arrow points up with on delay and down with off delay. This is best remembered by using the analogy of what would stay on or off a shelf. So ^ is staying on the shelf and v is falling off of the shelf.
  12. On delay timers have what type of contacts and what type are associated with off Delay? How can this be remembered? NJATC, Motor Controls: timers, 2010, PP 132
    • Both start with and NO or NC no letters are repeated in the on delay timer. Answer: ON DELAY- NOTC and NCTO
    • OFF DELAY- NOTO & NCTC. The letters are repeated in the OFF DELAY timer.
  13. There are two mechanical timers that are used in industrial applications, what are they? NJATC, Motor Controls: timers, 2010, PP 133
    • The synchronous timer and the dashpot timer are used in these applications.  The solid state electronic timer would be sensitive to heat.
  14. A synchronous timer, also referred to as an interval or on/off timer, will alternate energizing and de-energizeing a load at a specific rate. Synchronous timers will energize for the same amount of time that the load will remain de-energized. For mechanical relay applications, the relay contacts will alternate between closed and open. The amount of time the contacts are closed will equal?
    the amount of time the contacts are open.
  15. In a Synchronous timer when the triggers are gold or silver pegs inserted on the periphery of the rotating dial this indicates what by color? NJATC, Motor Controls: timers, 2010, PP 133
    Gold is the ON time setting and Silver is the OFF time setting.
  16. The Electronic or solid-state time delay timer has a time delay with ranges from what? NJATC, Motor Controls: timers, 2010, PP 135
    Fractions of a second to hundreds of minutes, and is considered extremely accurate, describe this type of timer.
  17. Timers with or without external triggers usually have what? NJATC, Motor Controls: timers, 2010, PP 135
    Without external triggers these usually have 8 pin bases and with external trigger requirements use an 11 pin configuration.
  18. The term "dry contact" on the external control switch of a non-programmable electronic timer indicates what? NJATC, Motor Controls: timers, 2010, PP 135
    The term indicates that the external switch contacts must have low current switching characteristics.
  19. What type of timer rarely has instantaneous contacts? NJATC, Motor Controls: timers, 2010, PP 135
    Single function timers rarely have these.
  20. The contacts of solid-state timers have limited current carrying capacity, usually less than how many amps? NJATC, Motor Controls: timers, 2010, PP 135
    These contacts on this type of timer usually have less than 10 A current carrying capacity.

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johnbowens
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Motor Controls: Timers
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2017-05-01 00:22:01
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NJATC, Motor Controls: timers, 2010
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