Alternators

Problem 611: There are two alternators, 100 kW, 3-phase in parallel are driven by shunt motors whose speed-load characteristics are as follows: Alternator No.1, no-load speed 600 rpm and the full-load speed 530 rpm, while alternator No. 2, no-load speed 590 rpm and full-load speed 550 rpm. For what load will the alternator divide the load equally?

Problem 612: There are two alternators, 100 kW, 3-phase in parallel are driven by shunt motors whose speed-load characteristics are as follows: Alternator No.1, no-load speed 600 rpm and the full-load speed 530 rpm, while alternator No. 2, no-load speed 590 rpm and full-load speed 550 rpm. What is the greatest load that can be delivered without overloading either alternator?

The pitch factor for third harmonic in an alternator having 18 slots per pole and coil span 5/6 of pole pitch is _.

Calculate the average voltage generated in a six turn full pitch coil of a 60 cycle alternator if the flux per pole is \(7.2 \times 10^{5}\) maxwells.

A three-phase, 60 Hz wye-connected wound rotor synchronous generator rated 10 kVA, 230 V has a synchronous reactance of 1.2 ohm per phase and an armature resistance of 0.5 ohm per phase. Calculate the percent regulation at full load with 0.8 lagging power factor.

For a coil having a span of 2/3 of pole pitch, the coil span factor is

The pitch factor for 3rd harmonic in an alternator having 18 slots per pole and coil span 5/6 of pole pitch is

A 6.6 kV Y-connected, 3-phase alternator has a synchronous reactance of 6 Ω per phase and a negligible resistance At a certain field current, the armature is known to induce 5.8 kV per phase. Calculate the maximum power that can be developed by the alternator at this excitation.

A three-phase alternator has 6 slots per pole per phase. Determine the distribution factor.

For a 36-slot 4-pole three phase full-pitch distributed winding, what is the percent reduction in the generated voltage?

A winding is short pitched by 60 degrees electrical. Its pitch factor is:

Two exactly similar turbo-alternators are rated 5 MW each. They are running in parallel. The speed load characteristics of the driving turbines are such that the frequency of alternator one drops uniformly from 60 Hz on no-load to 57.5Hz on full-load, that of alternator two from 60 Hz to 58 Hz. How will two machines share a load of 8,000 kW?

In a 10-pole synchronous machine, 20 electrical degrees are equivalent to how many mechanical degrees?

Calculate the average voltage generated in a six-turn full-pitch coil of a 25-cycle alternator if the flux per pole is \(7.2 \times 10^{5}\) maxwells.

A two-pole, three-phase, 50 Hz star connected ac generator has 9 slots/pole and 6 conductors/slot. What is the flux per pole if the open circuit terminal voltage is 1,100 volts? Take the coil span as unity.

A 500 kVA alternator operates at 80% of full load with an efficiency of 92 percent. If the load power factor is 0.8, calculate the total loss.

A three-phase, wye-connected, 6.25 kVA, 220-volt synchronous generator has a reactance of 8.4 ohms per phase. Using the rated kVA and voltage as base values, determine the per unit reactance.

A two-pole alternator is running at 1,500 rpm. What is the angular velocity?

Calculate the effective voltage in one phase of an alternator, given the following particulars: f = 60 cps; turns per phase N = 240; flux per pole = \(2.08 \times 10^{6}\) maxwells.

A three-phase 60 Hz wye-connected wound rotor synchronous generator rated at 10 kVA, 230V has a synchronous reactance of 1.2 ohm per phase and an armature resistance of 0.5 ohm per phase. Calculate the percent regulation at full-load with 0.8 lagging power factor.