FLYWHEEL BASED BUS

2. A Gyrobus is an electric bus that uses flywheel
energy storage, not overhead wires like
a trolley bus. The name comes from
the Greek language term for flywheel, gyros.

3. A FLYWHEEL is a
rotating mechanical
device that is used to
store rotational energy
Its work on the principle
of conservation of
energy. it basically
stored the energy and
deliver it whenever
required

4. OThe concept of a flywheel-
powered bus was
developed and brought to
originality during the 1940s
by Oerlikon (of Switzerland),
with the intention of creating
an alternative to battery-
electric buses for quieter,
where full overhead-wire
electrification could not be
justified.
HISTORY

5. Rather than carrying an internal
combustion engine or batteries, or
connecting to overhead power lines, a
gyrobus carries a large flywheel that is
spun at up to 3,000 RPM by a "squirrel
cage" motor/generator.
Working Principle:-

6. O The flywheel was positioned in the centre of the
chassis between the axles. This disc weighing 1.5t
and with a diameter of 1.6m was enclosed in an
airtight chamber filled with hydrogen gas at a reduced
pressure of 0.7 bar to lower "air" resistance. The
flywheel would spin at a maximum of 3000rpm.

8. Power for charging the flywheel was sourced by
means of three contact blades mounted on the
vehicle's roof, which contacted charging points
located as required or where appropriate (at
passenger stops en route, or at terminals, for
instance).

9. OCharging a flywheel took between 30
seconds to 3 minutes; in an effort to
reduce the charge time, the supply
voltage was increased from 380 volts
to 500 volts.
OGiven the relatively restricted range
between charges, it is likely that
several charging stops would have
been required on longer routes, or in
dense urban traffic.

10. In this fig. the energy is
stored into the flywheel. To
obtain tractive power
capacitor would excite the
flywheel charge motor so that
it becomes a generator

11. O In normal operation the flywheel could slow
down from its initial 3000 rpm to 2100 rpm. In
emergencies the speed could further be
reduced to 1500 rpm, but this would negatively
affect the performance of the vehicle. Below
this speed a proper functioning of the
transmission could no longer be guaranteed.
O Under normal conditions, the Gyrobus could
cover 5 to 6km between charges (taking stops
and traffic into account). A charge would then
take two to five minutes.
O In idle mode, the flywheel could continue
spinning for more than ten hours.
O A recharge from standstill could take 22
minutes.

12. ADVANTAGES:-
O Quiet.
O Pollution-free.
O Conservation of resource
O No fuel required
O Runs without rails.
O No need of over head wire.
O Can operate flexibly at varying
distances.

13. Disadvantages:-
O Weight: a bus which can carry 20 persons and has
a range of 5 km (3.1 mi) requires a flywheel
weighing 3 tone .
O The flywheel, which turns at 3000 revolutions per
minute, requires special attachment and security—
because the external speed of the disk is 900 km/h
(560 mph).
O Driving a gyrobus has the added complexity that
the flywheel acts as a gyroscope that will resist
changes in orientation, for example when a bus
tilts while making a turn, assuming that the
flywheel has a horizontal rotation axis.

14. Conclusion
O One of the main obstacles facing the Gyrobus was its
inability to gain a firm market presence and so cut
down manufacturing costs through economy of
scale.
O In today's environment, many of the factors that
disadvantaged the Gyrobus have changed.
O Fuel prices are rising and concerns over pollution
and smog have led to experiments with such
inefficient and dangerous storage technologies as
hydrogen cells (which appear to be more in political
favor than technologically sound).
O Would a simpler, safer and more comfortable
alternative not do the same in a friendlier manner?
O Modern power electronics would help reduce power
consumption whilst also enabling faster charging.
Modern materials could help reduce the overall
weight of the bus while retaining the required