329 Flashcards
Motor Power Connections and NEMA Enclosures
How Many Leads does a General Purpose Dual Voltage 3 PH Motor have
9 leads.
How Many Leads does a Dual Voltage 3 PH Motor with a Wye Start / Delta Run Come with
12 leads.
How are the Windings for a Dual Voltage Wired
Its is wired in series for the higher voltage and in parallel for the lower voltage. And the current in the windings does not change. But the circuit current will be halved if changing from a low voltage system to a high voltage system. The high voltage system has half the current as the low voltage one. Line current changes but winding current docent
What Additional Leads will some Motor Starters with both Thermal and Overload Protection Come with
P leads, they function to connect overload protection to the motor. It is like a middle man between overload relay (protection) and a (T leads) motor.
Can a Wye or Delta Power Supply Feed a Motor with either a Delta or Wye Configuration
Yes. But if it is a motor with 9 leads (wye) it cant work, the opposite is true for a delta wound motor with 6 leads. That would just be fine.
What are the Types of Motor Starter Enclosure Classifications
Open type(no enclosure), NEMA, or IEC.
Where would you Install an Open Type Enclosure
In a control cabinet or motor control center (MCC)
What is a Motor Control Center (MCC)
This is an enclosure that houses both the OCPD for a motor and its starter as well. It sometimes comes with a meter that reads info conditions like voltage, current, andphase circuit conditions. The MCC take up less space, it is a cabinet.
What does NEMA Stand for
National Electrical Manufacturers Association
What does the IEC stand for (In reference to Motor Starters)
International Electrotechnical Commission
What is the Range of NEMA Motor Starters and Contactor Sizes
Sizes: 00 (smallest, also called “two ought” or “double ought”) - 9 (biggest)
How are IEC Contactors and Starters Sized
In a none standardized way, It is designed based on the application requirements needed, these are called utilization categories. The starters are selected for particular applications.
What are a Few Things that can Affect the Operational Life of a Contactor or Starter
Temperature, vibration, altitude, dust, shock, chemical corrosion, etc.
Which would Require More Consideration for Circuit Design a NEMA or IEC Starter
An IEC starter would.
Where is the Enclosure Selection Table Located in the NEC
Table 110.28. It is referencing NEMA 250.
What Section Covers OSHA’s Rules on Material Handling, Storage, Use, and Disposal
OSHA’s subpart H of their construction standards.
What are the Rules for Material Storage in a Budling Under Construction
No material should be placed within 6ft of inside floor openings and 10ft of an exterior wall that is lower than the height of the material being stored.
How is the Maximum Height of Stored Brick Stacks
Not more than 7ft high. A loose stack of bricks past 4ft must be tapered and for masonry 6ft.
What is the Maximum Height of Lumber Piles
20ft. If Stacked Manually 16 ft.
What Height does OSHA Require a Chute for Dropping Materials Outside the Building Exterior Walls
20ft. but if you are dropping material through the building floors, barricade the area 42inches high and 6 ft wide
A Dual Voltage 3 PH Motor has how many Windings per Phase
2 Windings.
