1. ADVANCES IN
MAGNETIC GEARS
By Harshal R. Borole
Roll no. ME 11804
Guided by
Mrs. S. B. Desai

2. EARLIER RESEARCH
•A magnetic gear topology which employed the variable
reluctance principle was proposed.
It had much better utilization of magnetic circuit.
But it’s torque transmitting capability and efficiency
were less than 5kN/m³ & 35%
•Magnomatics is one of the leading company who
pioneered many of the high torque magnetic gears.
•Research on magnetic gears started in early 20th
century.

3. INTRODUCTION
• Magnetic Gears Offer Significant Potential
advantages Compared With Mechanical Gears
• Magnetic gears basically use permanent magnets
to transmit torque between input and output shaft.
• New Magnetic Gears show promise as
REPLACEMENTS for mechanical Gears.
• It utilizes net of all magnetic poles to
simultaneously transmit torque.

4. In this external gearing structure, at any instant, only a
fraction of permanent magnets contribute to torque
transmission.

5. •In this proposed topology, rare earth magnets are employed on
both the inner and outer rotor.
•It also has ferromagnetic pole pieces between the two rotors.
•The advantage with this topology is that all the permanent magnets
contribute to torque transmission.

6. INNER TYPE MAGNETIC GEAR
•From the figure, it is quite cleat that more magnets get
active if no. of poles on the inner ring are closer no. of
poles on the outer ring.
•If no. of poles on inner ring is equal to no. of poles on the
outer ring, gearing ration is unity.

7. GEAR TOPOLOGIES PROPOSED IN
THE PAST
• Different gear topologies were proposed for the
better torque transmission.
 Magnetic disc gear.
 Magnetic worm gear.
 Magnetic planetary gear.
 Magnetic shutter gear.
 Cycloid gear.

8. WHY CYCLOID GEARS ?
•In the classical outer type magnetic gear arrangement, it
is clear that a lot of magnets are inactive and cannot
assist in transmitting torque.
•Also volume taken up from gear is quite high because of
the two rings separated.
In order to reduce the volume and increase the
interaction, inner type magnetic arrangement is used.
•But with the inner type arrangement with almost equal no.
of poles on the two rings, the gearing ratio is very low.
So in order to improve the gearing ratio, cycloid principle
is used.

9. DESIGN OF HIGH PERFORMANCE
MAGNETIC GEAR
•The gear ratio for magnetic gear is given by,
Gr = pl / ph
Where pl= no. of pole pairs on the outer permanent
magnet rotor.
ph= no. of pole pairs on the inner permanent
magnet rotor
•Mostly gear ratios of 5.5:1 , 5.75:1 , 11:1 are selected.

10. DIFFERENT SECTION VIEWS OF CYCLOID
GEAR

11. TORQUE TRANSMISSION
Variation of max. torque on low speed rotor with radial
thickness of pole pieces for 5.5 : 1 gearing ratio.

12. ANALYSIS OF THE TORQUE TRANSMISSION
• The graph shows the variation of max. torque on low
speed rotor with radial thickness of stationary pole
pieces.
• It can be seen that an optimum radial thickness for
the pole pieces exists for which torque transmission
capability is maximum.
• It is also seen that the combination of the no. of pole
pairs on the low speed and high speed rotors and
the no. of stationary pole pieces has significant
influence on max torque transmitting capability.

13. DYNAMIC LOAD TEST ON CYCLOID
GEAR

14. PERFORMANCE ANALYSIS
•Three input velocities were tested and different loads
were applied.
•The best efficiency was measured at 50 rpm as 94%

15. INFLUENCE OF THE GEOMETRY
DIMENSION & NO. OF POLE PAIRS
• This analysis explains the size effect of the radius of cylindrical
magnets.
• From curves, it can be seen that peak is shifted from 4 poles to 8
poles to 12 poles with the increasing outer radius of magnets.

16. ANALYSIS OF CYCLOID PERMANENT
MAGNETIC GEAR
Variation of max. torque of two magnetic
gears as a function of transmission ratio

17. ADVANTAGES
 Reduced maintenance and improved reliability
 Lubrication free
 Higher efficiency than conventional gears
 Precise peak torque transmission and inherent
overload protection
 Physical isolation between input and output shafts
 Inherent anti-jamming transmission
 Significantly reduces harmful drive train pulsations
 Very low acoustic noise and vibration

18. APPLICATIONS
• Renewable Energy
 Wind And Marine Energy
• Automotive Applications
 Hybrid Electric Vehicle
 Auxiliary Drives
• Naval Propulsion Systems
• Manufacturing Machinery
• Machining Operations like drilling, milling etc.
• Pump Applications

19. CONCLUSION
• A new high performance magnetic gear topology
was presented.
• It has been shown that choice of design parameters
has a significant influence on the torque transmission
capability.
• Cycloid gear profile was explained with its need and
advantages.
• Since magnetic gears have no. of advantages over
the mechanical gearing, its use in future in practical
applications is inevitable.

20. THANK YOU