The motor time tE for increased safety motor is prime safety parameter. The higher value of time tE means insulating system of Ex e motor is able to withstand the locked condition for long time so motor will be more safe for long duration during in specified abnormal condition in hazardous area.
What is short time rating of motor?
A short time rating of an electric motor can be defined as the extrapolated overload rating of the motor which it can supply for the specified short time without getting overheated. Now a days the machines are being designed and manufactured for short duration having sufficient overload torque capability.
What do motor codes mean?
Codes are defined in MG 1-10.37. 2 by a series of letters from A to V. Generally, the farther the code letter from A, the higher the inrush current per hp. A replacement motor with a “higher” code may require different upstream electrical equipment, such as motor starters.
What does code l mean on a motor?
NEMA – The National Electrical Manufacturer’s Association – who sets the design standards for motors, has established a NEMA Code letter designation to classify motors by the ratio of locked rotor KVA per horsepower. … less than 1 hp: Locked Rotor Code L, 9.0-9.99 KVA. 1 1/2 to 2 hp: Locked Rotor Code L or M, 9.0-11.19.
How is CDF of a motor calculated?
2. Cyclic duration factor : (CDF) : The ratio between the period of loading including starting and electric braking and the duration of the duty-cycle expressed as percentage. 3. Starting : The process of energizing a motor to bring it upto rated speed from rest.
Crane Duty Motors.
|Slarts/hour||40% CDF||60% CDF|
Why is motor rated in kW?
Motor is rated in kW since it specifies the capacity of the motor to drive its load. It is the active power (kW) that is of interest when a motor drives a load. The motor converts the active power that it draws from the mains into mechanical power that the load consumes/demands. … Thus, a motor is rated in terms of kW.
How can you tell if a motor is VFD?
Three major factors should be considered when determining if a motor is compatible with a VFD: the motor winding insulation, motor bearings and pump operating speed range.
What does CYC mean on a motor?
CYC stands for “Motor Cycle” How to abbreviate “Motor Cycle”? “Motor Cycle” can be abbreviated as CYC.
How do I know if my engine is inverter duty?
Motor insulation systems that are rated for inverter use will be specified on the motor nameplate (or a sticker). These systems should have wire rated for a minimum of 1600 volt spikes, F or H class insulation, and will be processed with 100% sold resin in a vacuum pressure impregnation (VPI) system.
How do I know if my rotor is locked?
To find LRA and starting kVA enter nominal operation voltage (such as 120 or 240), HP value, code letter from the nameplate label, and hit “Calculate” button. The general equation for single-phase devices is the following: LRA=1000*(kVA/HP)/Voltage. Note that this defines starting current at full nominal voltage.
Which power is mentioned on a name plate of a motor?
Which power is mentioned on a name plate of a motor? Explanation: Name plate of the motor shows rated values i.e. rated speed, rated current, rated voltage. It also shows output power available at shaft when all other quantities are set to rated values.
What are 4 common types of motor enclosures?
The most common types of enclosures are:
- Open Drip Proof (ODP) …
- Weather Protected (WP1 / WP2) …
- Totally Enclosed Fan Cooled (TEFC) …
- Totally Enclosed Non-Ventilated (TENV) …
- Totally Enclosed Air Over (TEAO) …
- Totally Enclosed Forced Ventilated (TEFV) …
- XP (Explosion Proof)
How do you read motor specs?
- Frame Designation (FR) – this is typically a two or three digit number followed by one or more letters that identifies important mounting dimensions.
- Manufacturers Type (TYPE). …
- Horsepower Output (kW). …
- Time Rating or duty (DUTY). …
- Max Ambient Temp. …
- Insulation System Designation. …
- Speed At Rated Load (RPM). …
- Frequency (HZ).
How do you check a motor kW without a nameplate?
Use a strobe tachometer to determine motor RPM and then set up a generic motor in the database for that RPM. If loading cannot be provided by the operator use the acquired data and RPM to approximate loading. You can view the power factor for a value around 88 to 92 to approximate full load.