Exam (elaborations)
Electric Motors Controls BOMA Pre-Quiz 2024/2025 Graded A+
- Course
- Institution
Electric Motors Controls BOMA Pre-Quiz 2024/2025 Graded A+
[Show more]
Content preview
Electric Motors Controls BOMA Pre-Quiz2024/2025 Graded A+
_____ converts between electrical and mechanical power. - ANSWER-Motor,
Generator, alternator.
________ have overloads and _________ do not? - ANSWER-Starters, contactors
"Cross firing " is? - ANSWER-Arcing across a double-brake contact
A "ladder rung" in a electrical diagram refers to? - ANSWER-A single line in the diagram
A 7200 rpm motor at 60hz has? - ANSWER-Two poles
A component that has high resistance in one direct and low in the other is a ? -
ANSWER-Diode
A contactor with two sets of contacts is? - ANSWER-2 pole contactor
A defective starter would likely not cause? - ANSWER-Damage bearings, excessive
vibrations, high voltages,
A device used to measure the rotating speed of a motor is called a? - ANSWER-
Tachometer
A double-break contacts function is to reduce the current of each arc. - ANSWER-True
A four-pole induction motor operates with a line frequency of 60 hz. What is the speed
at which the field is rotating in revolutions per minute? - ANSWER-1800
A fuses interrupting capacity is based on ? - ANSWER-The application it is used in
The maximum amperage it can interrupt without being damaged.
Manufacturers design
A latching circuit consists of? - ANSWER-Start and stop push buttons.
A magnetic field is created when? - ANSWER-Electricity flows
A magnetic field? - ANSWER-Is created when current flows,
Surround a magnet,
Is invisible
A motor - ANSWER-Converts electrical energy into mechanical energy.
, A soft start is used to? - ANSWER-Reduce starting current
A sticky armature in a contactor will most likely? - ANSWER-Burn out the coil
A tachogenerator? - ANSWER-Generates a voltage based on speed.
A temporary magnet is? - ANSWER-An electromagnet
A voltage monitor relay is used for? - ANSWER-Starting backup generators.
AC motor speed is determined by? - ANSWER-The number of poles.
an armature is - ANSWER-The movable portion of a contractor.
An electrical motors nameplate? - ANSWER-Must me on every motor in the plant
An induction motor will develop maximum torque at what speed? - ANSWER-70% to
80%
Arc chutes. - ANSWER-Help confine the arcs.
At a 60 hz frequency, a two-pole motor will operate at? - ANSWER-3600 rpms
Batteries energy capacity is measured in? - ANSWER-Amp-hours
Batteries have two rated values. - ANSWER-Voltage and amp-hours
Being wired across the line refers to? - ANSWER-A circuit that automatically restarts
after power failures.
Branch circuit conductors, must be rated at least _____ of the motors full load capacity.
- ANSWER-125%
Contacts excessively cycled: - ANSWER-Causes the contacts to overheat
DC arcs. - ANSWER-Are the most difficult to extinguish.
Drum switches reverse motors by swapping leads in a 3-please system. - ANSWER-
True
Fuel for diesel generators is often stored in a? - ANSWER-Day tank
How are normally closed contacts indicated on a ladder diagram? - ANSWER-An
underline
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller CLOUND. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.99. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
82871 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now