The Dahlander motor is a two speed motor that offers a 1:2 speed switching. It requires a special dual speed starter with three contactors and two overload protection relays to operate in either star or delta configurations for different speeds. Dahlander motors can be wound for constant power, variable torque, or constant torque applications and offer flexibility to obtain two fixed RPMs from a single motor.

1. Dahlander Motors
The Dahlander motor is a two speed motor that offers a 1:2 speed switching. It
is a specially wound pole switching motor requiring a special dual speed
starter.
The motor is wound as star or delta with center taps on each leg of the
winding. The motor is connected in star or delta for one speed and in "double
star" for the other speed.
The starter requires three contactors (five for reversing):
Speed 1 main contactor
Speed 2 main contactor
Star contactor that can differ in its connection depending on the motor layout.
Two over load protection relays are required, one in series with each of the
main contactors.
Dahlander motors can be wound for constant power, variable torque or
constant torque applications.
A constant power Dahlander motor is would as a delta motor, and a constant
torque motor is wound as a star.
I’ve done the drawings showing reversing starters as this is what I used to
work on.
HF = High forward
HR = High reverse
L = Low star
LF = Low forward

2. HF = High forward
HR = High reverse
H = High star
LF = Low forward
LR = Low reverse
HF = High forward
HR = High reverse

3. H = High star
LF = Low forward
LR = Low reverse

4. Application
3 Phase AC Squirrel Cage Induction Motor - Dahlander
Type
With the availability of 3 Phase AC Squirrel Cage Induction Motor - Dahlander Type
becoming common, the use of 3 Phase AC Squirrel cage Motor became very
common & today it holds 90% of the total market share. The simplicity in operation
with the 3 phase voltages & immediate torque made it a very common motor.
Dahlander motor is just an extension with the flexibility that from 1 motor you can get
2 different fixed rpm, this is basically by changing the coil connections inside the
motor. This Model is the Industrial /Educational model suitable for demonstrating to
students the complete know of the Basics, Components, Starting methods, Wear &
Tear & Maintenance of these motors packaged in small rating. Students can make
connections of their own with the help of the terminations provided for study of
features viz Starting methods, Speed control, Speed -Torque, Effect of Phase angle,
Study of Cogging/Crawling, Effects of Single phasing, Effect of voltage imbalance
operation, Blocked rotor test.
Specifications :
 Power ratings available : 350W / 750W / 1KW /2 KW / 3KW/ 5KW
 Voltage Input: 440V AC 50hz
 RPM: 2pole & 4pole, (1400/2880), other options are (6pole/4pole)
 Single / Double shaft extension, TEFC, IP44, IC01, B3, Class-B, S1,
Casting body
W21 - Cast Iron Frame - Dahlander 4/2 Pole - Constant Torque
Premium efficiency cast iron frame IP55 Dahlander two speed 4/2 pole
constant torque motor

5. Applications
Pumps- Fans- Crushers- Conveyors- Machine tools- Milling applications- Centrifugal
machines- Presses- Elevators- Looms- Grinders- Woodworking- Packaging equipment
DSDM-300 Dahlander Motor
300 is a dual speed Dahlander motor with a six lead connected stator-The Model DSDM
diagrammed area located on the front ofwinding wired to terminals located within a schematic
a terminal panel mounted on a totally enclosed terminal box attached to the machine base.
TEFC - Two Speed Dahlander - Variable Torque - One Winding
Fans-Pumps-Blowers-Conveyors-Farm equipment-Saws

6. TWO SPEED DAHLENDER MOTERS MODELS
8223,8224 AND 8225
1) MODEL 8223 :
2)MODEL 8224 :

7. 3)MODEL 8225

8. ASWAN UNIVERSITY
FACULTY OF ENGINEERING
ELECTRICAL ENGINEERING DEPARTMENT
engineer: Ahmed Amin Hassan
Slides About
" Dahlender Motor "