Transcript Written Pole Technology

WRITTEN-POLE
ELECTRIC MOTORS
Presented by:
Nidhi Pansari (3rd elec)
Preeti Baid (3rd elec)
CONTENTS
•LIMITATIONS OF CONVENTIONAL
TECHNOLOGY
•CONSTRUCTION
•WRITTEN-POLE TECHNOLOGY
•OPERATION
•OPERATIONAL BENEFITS
•ADVANTAGES
•WEATHER CONDITIONS
•APPLICATIONS
•CONCLUSION
2
LIMITATIONS OF
CONVENTIONAL TECHNOLOGY
1.Dependence of speed on no. of poles of
rotor.
speed = 120 X frequency
no. of poles
2.The machine must have even no. of poles
and deviating from this condition will
cause unstability at its rated speed.
AN INNOVATIVE
PATENTED TECHNOLOGY
• In the 1990’s, with support from the
EPRI, the Precise Power Corporation
of Bradenton, Florida, developed a
new concept in electric motors called
the Written Pole® electric motor.
WRITTEN-POLE
TECHNOLOGY
• The patented Written-Pole® Technology allows the
magnetic pole pattern on the magnet layer to be
changed to a desired pattern while the machine is
rotating and therefore breaks the relationship
between rotor speed and output frequency.
CONSTRUCTION
Contd..
• Written Pole motors use similar
construction techniques found in
conventional motors.
• A continuous layer of ferrite magnets on
the surface of the rotor, along with a
high-density exciter winding contained
within the stator winding .
• The basic platform consists of a
conventional steel shaft inserted into a
lamination stack containing a high
resistance rotor cage.
Contd…
• The high resistance cage is a key factor in
limiting the starting current of WrittenPole motors.
• The stator lamination stack is constructed
using low loss electrical steel laminations.
• The concentrated excitation windings are
contained within the stator structure and
are located between the main stator
windings.
OPERATION
• A written-pole motor employs one of
three modes of operation based on the
rotational speed of the machine:
1. START MODE
2. WRITTEN POLE MODE
3. RUN MODE
.
OPERATIONAL
BENEFITS
Feature
Conventional
WP
Speed
Efficiency
Power factor
Full-load power
3,560rpm
85%
90.5%
53kW
3600 rpm
93%
100%
40kW
Full-load torque
73.7 ft-lb
73 ft-lb
Starting torque
Full-load current
Locked rotor current
Cost (p.u.)
88 ft-lb
219 amps
1450 amps
1.0
82 ft-lb
173 amps
312amps
1.2
ADVANTAGES
1. Low starting current requirements
2. Energy efficient operation
3. Unity power factor operation
4. Simple construction
5. Low temperature rise
6. High inertia starting
7. Instantaneous restart capability
8. Ride through characteristics
9. Three-phase applications
WEATHER CONDITIONS
• The Written-Pole motor is designed to
operate in ambient temperatures ranging
from 32ºF to 104ºF.
• However,test results show that WrittenPole motors have reliably operated in
temperatures ranging from 42ºF to 122ºF.
• They may be operated safely in the open air
if there is adequate protection from direct
rain.The motor base must be mounted on
a raised concrete pad or steel frame to
avoid exposure to standing water.
A WRITTEN POLE RIDE THROUGH
MOTOR USED IN A FARM
APPLICATIONS
• Regulation of output voltage and frequency in
electric generators,without relying on external
regulators or power electronics.
• In a family of single and three-phase motive power
and power protection systems used by many
customers including the US Weather
Service,NASA,Federal Aviation Authority,US Air
Force and many commercial and industrial
customers.
• To create a simple,rugged power protection unit
combining Written-Pole motors and generators
with an integral flywheel
AWARD WINNING
TECHNOLOGY
• A recipient of the R&D 100 Award in 1994,
Written-Pole technology was recognized
by R&D Magazine as one of that year's
most technologically significant
innovations.
• The technology has also been recognized
by numerous technical organizations
including the Professional Society of
Engineers in the United States.
CONCLUSION
• The written-pole motor, developed by
Precise Power Corporation, is a motor
design that allows for the operation of very
large single-phase motors.
• This unique product has applications
virtually anywhere that three-phase power
is either not available, or is not economical
to provide.
• This motor technology has the additional
benefit of being able to ride through brief
service interruptions on single-phase power
lines.
THANK
YOU!
WRITTEN POLE TECHNOLOGY