DC Generators
For a D.C. machines laboratory following type of D.C. supply will be suitable

Synchronous motor D.C. generator set
Mercury are rectifier
Induction motor D.C. generator set
Rotary converter

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DC Generators
When two D.C. generators are running in parallel an equalizer bar is used

To increase the generated e.m.f.
To reduce the combined effect of armature reaction of both the machines
So that the two identical machines will pass approximately equal currents to the load
To increase the series flux

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