Alternator

Probably will extend the life, since there is no heat/wear/friction when in stop mode.

It this better than continuous running? Probably, but I'd ask the people who made your specific alternator, since we don't have any information to help.

It depends on why the alternator rotor stops spinning. If it is because somebody turns the engine OFF then not much of a difference in wear will happen. If instead the alternator rotor stops turning in a front engine vehicle because the vehicle has slammed into a rocky cliff at 100 mph then....

it blows up

What kind of Battery is in the vehicle during start-stop operations? What is it's DOD, amp hours, and other performance charachteristics? Which is cheaper to abuse?

PL. give complete details of type, capacity, type of insulation type of cooling etc. to enable understand and reply.

Continous thermal cycling, does stress mechanically the insulation by expansion variations on different materials, could create micro cracking and make windings more prone to humidity deterioration. But that is very theoretical and depends on construction and materials quality and of course the environment the machine works. S.M.

Dear Mr.ataul,

Frequent start and stop certainly introduces stress and strain on the system.

If I understand, your quiery correct, you intend to increase the life of the alternator. Is that right.?

If so do the following.

1. Run at optimum capacity and majority of operation keep the load around 85-90 %.

2. Maintain all the operational parameters like vibrations, bearing temp.rise, winding temp. rise with in the value indicated in in the Instruction Manual/Manufacturer's Instruction.

3. The Power Factor should never go below the designed value.

4. Use soft starters so that starting current is limited.

5. Take care of the Gd^2 value of the machine and starting aspect so that the starting current is taken care. If need be use grid resistance in the rotor circuit (compulsorily the motor should be Slip-Ring type) as it developes more Torque, since it is governed by the equation T = k x s/R where T is the Torque, k is the constant for the system, " s " is the slip of the Motor and R is the Resistance to be included to the rotor circuit.

6. Use High Slip Motor or use 2 motors of Half Capacity on both sides of the equipment if possible.

All these thing to be taken care while designing stage itself.

DHAYANANDHAN.S

have any equation for calculating the running hour which will help to follow maintenance work ( etc 25000 hour maintenance )

T=ΣΔtn

This formula will only work if one records the start and stop time of each and every operation (n).

T is for which time

Alternator running hour is 12000, start counter count 500.

Call the manufacturer.

Ambient conditions will play a major part in how well this air-cooled generator ages. As others have stated thermal cycling will have a significant effect on the life of the insulation system, what's missing here is the on-off interval coupled with the ambient air conditions and whether the generator was designed for this type of duty.

If the on time is short relative to the off time then the generator may never reach a steady state temperature, if the off-time allows the generator to cool below the dew point then moisture condensation will become a major concern; both of these conditions lead to premature insulation aging. This one of the reasons why large utility generators are generally sealed units with hydrogen cooling systems.

There are mechanical considerations as well, perhaps less of a concern on relatively small units such as this one though. There may be differential expansion problems as the rotor and stator expand and shrink at different rates, this may cause unanticipated stress on the bearing system. This is just one of the differences between a generator built for cycling duty vs. one built for base load duty, there are plenty of others.

Lyn is right, you need to call the manufacturer