TYPES
OF MOTOR:
ELECTRIC MOTORS |
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DC
MOTORS |
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AC
MOTORS |
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OTHER
MOTORS |
DC Shunt Motor |
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Induction
Motor |
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Stepper
Motor |
Separately Excited Motor |
|
Synchronous
Motor |
|
Brush-less Motor |
Series Motor |
|
|
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Hysteresis
Motor |
MPMDC Motor |
|
|
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Reluctance
Motor |
Compound Motor |
|
|
|
Universal
Motor |
An induction motor or asynchronous
motor is an AC electric motor in which the electric
current in the rotor needed
to produce torque is obtained by electromagnetic induction from
the magnetic field of the stater winding. An
induction motor can therefore be made without electrical connections to the
rotor.
An induction motor's rotor can be either wound type (Slip ring rotor) or squirrel-cage type.
A synchronous electric motor is an AC
motor in which, at steady state, the
rotation of the shaft is synchronized with the frequency of the
supply current; the rotation period is exactly equal to an integral number
of AC cycles. Synchronous motors contain multi phase AC electromagnets on
the stator of
the motor that create a magnetic field which
rotates in time with the oscillations of the line current. The rotor with
permanent magnets or electromagnets turns in step with the stator field at the
same rate and as a result, provides the second synchronized rotating magnet
field of any AC motor. A synchronous motor is termed doubly fed if it is supplied
with independently excited multiphase AC electromagnets on both the rotor and
stator.
The synchronous motor and induction motor are the most widely
used types of AC motor. The difference between the two types is that the
synchronous motor rotates at a rate locked to the line frequency since it does
not rely on current induction to produce the rotor's magnetic field. By
contrast, the induction motor requires slip: the
rotor must rotate slightly slower than the AC alternations in order to induce
current in the rotor winding. Small synchronous motors are used in timing
applications such as in synchronous clocks, timers in
appliances, tape recorders and precision servomechanisms in
which the motor must operate at a precise speed; speed accuracy is that of
the power line frequency, which is
carefully controlled in large interconnected grid systems.
MOTOR
NAME PLATE:
Make |
|
|
|
Order No |
|
Frame |
324T |
Type |
SD 100 |
Service Factor |
1.15 |
HP/KW |
30 |
VOLTS |
415 |
AMPS |
40.8 |
Phase (Ø) |
3 |
R.P.M. (n) |
1485 |
Hz |
50 |
Duty |
S1 |
Power Factor (cosØ) |
1.0 |
Ingress Protection |
IP55 |
Weight |
556 lbs |
Class Insulation |
F |
Efficiency (ɳ) |
93.0 |
Connection |
|
Ambient |
0-50 °C |
NEMA Design |
A |
KVA Code |
|
DE Bearing |
|
Opp. DE Bearing |
|
Name Plate Terms |
Meaning |
Volts |
Rated
terminal supply voltage. |
Amps |
Rated full-load supply current. Some motor name plate have FLA
- Full load Current |
H.P. |
Rated motor output in Horse power |
R.P.M |
Rated full-load speed of the motor. |
Hertz |
Rated supply frequency. |
Frame |
External physical dimension of the motor based on the NEMA
standards |
Duty |
Motor load condition, whether it is continuous load, short
time, periodic, etc. |
Date |
Date of manufacturing. |
Class Insulation |
Insulation class used for the motor construction. This
specifies max. limit of the motor winding temperature. |
NEMA Design |
This specifies to which NEMA design class the motor belongs
to. |
Service Factor |
Factor by which the motor can be overloaded beyond the full
load. |
NEMA Nom. Efficiency |
Motor operating efficiency at full load. |
PH |
Specifies number of stator phases of the motor. |
Pole |
Specifies number of poles of the motor. |
Y |
Specifies whether the motor winding are Star (Y) connected or
Delta (Δ) connected. |
Safety Standard Symbol |
Specifies the motor safety standard. |
MOTOR
DUTY/ LOAD CYCLE:
The term duty defines the load cycle
to which the machine is subjected, including, if applicable, starting, electric
braking, no-load, and rest de-energized periods, and including their duration
and sequence in time. Duty considered as a generic term, for example, can be
classified as a continuous duty, short-time duty, or periodic duty.
Continuous
running duty (type S1)
For a motor
suitable to this duty type, the rating at which the machine may be operated for
an unlimited period is specified. This class of rating corresponds to the duty
type whose appropriate abbreviation is S1.
The duty type S1 can be defined as operation at a constant load
maintained for sufficient time to allow the machine to reach thermal
equilibrium.
Short-time duty (type S2)
For a motor
suitable to this duty type, the rating at which the machine, starting at
ambient temperature, may be operated for a limited period is specified. This
class of rating corresponds to the duty type whose appropriate abbreviation
is S2.
The duty type S2 can be defined as operation at
constant load for a given time, less than that required to reach
thermal equilibrium, followed by a time de-energized and at rest of sufficient
duration to re-establish the equilibrium between the machine
temperature and that of the coolant temperature.
A complete
designation provides the abbreviation of the duty type followed by an
indication of the duration of the duty (S2 40 minutes).
Periodic
duty (type S3-S8)
For a motor suitable
to this duty type, the rating at which the machine may be operated in a
sequence of duty cycles is specified. With this type of duty, the loading cycle
does not allow the machine to reach thermal equilibrium.
This set of ratings is linked to a defined duty type from S3 to S8 and
the complete designation allows identification of the periodic duty.
If no otherwise
specified, the duration of a duty cycle shall be 10 minutes and the cyclic
duration factor shall have one of the following values: 15%, 25%, 40%, 60%.
The cyclic duration factor is
defined as the ratio between the period of loading, including starting and electric
braking, and the duration of the duty cycle, expressed as a percentage.
Intermittent periodic duty
(Duty type S3)
DEFINITION –
The duty type S3 is defined as a sequence
of identical duty cycles, each including a time of operation at constant load
and a time de-energized and at rest. The contribution to the
temperature-rise given by the starting phase is negligible.
A
complete designation provides the abbreviation of the duty type followed by the
indication of the cyclic duration factor (S3 30%).
Intermittent periodic duty with starting (The duty type S4)
The duty type S4 is defined as a sequence of identical duty cycles,
each cycle including a significant starting time, a time of operation at constant load and a time de-energized and at a rest.
A complete
designation provides the abbreviation of the duty type followed by the
indication of the cyclic duration factor, by the moment of inertia
of the motor JM and by the moment of inertia
of the load JL, both referred to the motor shaft (S4
20% JM = 0.15 kg m2 JL = 0.7 kg
m2).
Intermittent periodic
duty with electric braking (The duty type S5)
The duty type S5 is defined as a sequence of identical duty
cycles, each cycle consisting of a starting time, a time of operation at
constant load, a time of electric braking and a time de-energized and at a rest.
A complete designation refers to the duty type and gives the same type of indication of the previous case.
Continuous-operation periodic duty (The duty type S6)
The duty type S6 is defined as a sequence of identical duty
cycles, each cycle consisting of a time of operation at constant load and a
time of operation at no-load. There is no time de-energized and at rest.
A complete
designation provides the abbreviation of the duty type followed by the
indication of the cyclic duration factor (S6 30%).
Continuous-operation periodic duty with electric braking (Duty type S7)
The duty type S7 is defined as a sequence of identical duty
cycles, each cycle consisting of a starting time, time of operation at constant
load and a time of electric braking. There is no time de-energized and at rest.
A complete
designation provides the abbreviation of the duty type followed by the
indication of both the moment of inertia of the motor JM and
the moment
of inertia of the load JL (S7 JM =
0.4 kg m2 JL = 7.5 kg m2).
Continuous-operation periodic duty with related load / speed (Duty type
S8)
The duty type S8 is defined as a sequence of identical duty
cycles, each consisting of a
time of operation at constant load corresponding to
a predetermined speed of rotation, followed by one or more times of operation at other
constant loads corresponding to different speeds of rotation. There is no time de-energized
and at rest.
A complete
designation provides the abbreviation of the duty type followed by the
indication of the moment of inertia of the motor JM and by the
moment of inertia of the load JL, together with the load, speed and
cyclic duration factor, for each speed condition (S8 JM =
0.7 kg m2 JL = 8kgm2 25kW
800rpm 25% 40kW 1250rpm 20% 25 kW 1000 rpm 55%).
Non-periodic
duty (type S9)
Duty with non-periodic load and speed variations
For a motor
suitable to this duty type, the rating at which the machine may be operated
non-periodically is specified. This class of rating corresponds to the duty type whose
appropriate abbreviation is S9.
The duty type S9 is defined as a duty in which generally load
and speed vary non-periodically within the permissible operating range. This
duty includes frequently appplied overloads which may greatly exceed the reference
load.
Duty with discrete constant loads and speeds (type S10)
For a motor suitable to this duty type, the rating
at which the machine may be operated with a specific number of discrete loads
for a sufficient time to allow the machine to reach thermal equilibrium is
specified.
The maximum permissible load within one cycle shall take into consideration all
parts of the machine (the insulation system, bearings or other parts with
respect to thermal expansion).
The maximum load shall not exceed 1.15 times the value of the load based
on duty type S1. Other limits as regards the maximum load may
be given in terms of limits of temperature of the winding. The minimum load may have the value zero, when
the machine operates at no-load or is de-energized and at rest.
This class of
rating corresponds to the duty type whose appropriate abbreviation is S10.
The duty type S10 is defined as the operation characterized by a
specific number of discrete values of load maintained for a sufficient time to
allow the machine to reach thermal equilibrium. The minimum load during a duty
cycle may have value zero and be relevant to a no- load or rest condition.
A complete
designation provides the abbreviation of the duty type followed by the indication of the
per unit quantities p/Δt for the partial load and its duration, and by the indication of the per unit quantity
TL which represents the thermal life expectancy
of the insulation system related to the thermal life expectancy in case of duty
type S1 with rated output, and by the quantity r which indicates the
load for a time de-energized and at rest (S10 p/Δt = 1.1/0.4; 1/0.3; 0.9/0.2; r/0.1 TL =
0.6).
INGRESS PROTECTION:
Ingress
protection ratings or IP ratings refer to the level of protection offered by an
electrical enclosure, against solids and liquids. In an environment where dust
or water could damage electronic components, a sealed enclosure is used to
prevent such ingress and safe house the electronics.
IP (INGRESS PROTECTION)
RATING GUIDE |
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SOLID |
LIQUID |
||
Level of Ingress Protection |
Level
of Ingress Protection |
||
1 |
Protected against a solid object greater
than 50 mm (such as a hand)(50 N of force) |
1 |
Protected against vertical falling drop of
water for 10 minutes at rate of 1 mm/min. |
2 |
Protected against a solid object greater
than 12.5 mm (such as a finger)(10N of force) |
2 |
Protected against diagonally falling (up to
15 Deg.) drop of water for 10 minutes at rate of 3 mm/min. |
3 |
Protected against a solid object greater
than 2.5 mm (such as a screwdriver)(3N of force) |
3 |
Protected against diagonally falling (up to
60 Deg.) spray of water for 5 minutes at 0.7 LPM at 80-100 kPa. |
4 |
Protected against a solid object greater
than 1 mm (such as a wire)(3N of force) |
4 |
Protected against water splashed from all
direction for 5 minutes at 0.7 LPM at 80-100 kPa. |
5 |
Dust protected. Limited ingress of dust
permitted. Will not interfere with operation of equipment. |
5 |
Protected against a 6.3mm water nozzle for
3 minutes at rate of 12.5 LPM at 30 kPa at a distance of 3 meter. |
6 |
Dust tight. No ingress of dust. |
6 |
Protected against a 12.5mm water nozzle for
3 minutes at rate of 100 LPM at 100 kPa at a distance of 3 meter. |
|
|
7 |
Protected against 30 minute submersion at a
depth of 1 meter. |
|
|
8 |
Protected against continuous submersion for
a long period at a depth of 3 meter. |
|
|
9K |
Protected against powerful, high
temperature water jets. |
Insulation
Classes for Electric Motors
NEMA (National Electrical Manufacturers Association) motor
insulation classes describes the ability of motor insulation in the windings to
handle heat. There are four insulation classes in use namely: A, B, F, and H.
All four classes identify the allowable temperature rise from an ambient
temperature of 40° C (104° F). Classes B and F are the most common in many
applications.
Temperature rises in the motor windings as soon as the AC motor is
started. As shown in the table below, the combination of ambient temperature
and allowed temperature rise equals the maximum rated winding temperature.
Allowable temperature rise is made up of the maximum temperature rise for each
insulation class plus a hot-spot over-temperature allowance. If the motor is
operated at a higher winding temperature, service life will be reduced. As a
rule,
a 10° C increase in the operating temperature above the
allowed maximum can cut the motor’s insulation life expectancy in half.
The table below shows the different insulation classes as defined
by NEMA:
Class |
Maximum
Ambient Temperature (°C) |
Maximum
Temperature Rise (°C) |
Hot-spot Over Temperature (°C) |
Maximum
Winding Temperature (Tmax)(°C) |
A |
40 |
60 |
5 |
105 |
B |
40 |
80 |
10 |
130 |
F |
40 |
105 |
10 |
155 |
H |
40 |
125 |
15 |
180 |
Hot-spot Over Temperature Allowance
Each insulation class has a margin allowed to compensate for the
motor’s hot spot. The hot-spot is a point at the center of the motor’s winding where the temperature is higher.
FRAME SIZE:
The two-digit frame number relates to the shaft
height in sixteenths of an inch. You can figure that a 48-frame motor will
have a shaft height of 48 divided by 16, or 3 in. Similarly, a 56-frame motor
has a shaft height of 3.5 in.
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