For the selected ideal steady-state reference, generated EMF is E = kΦn. If an ideal shunt field resistance Rf is connected across that EMF, If = E/Rf and field power is E²/Rf.
Shunt Generator and Field Circuit
Explore ideal generated EMF and shunt-field arithmetic for independently selected flux and speed.
Equation Used
- Machine constant, flux and speed are independently selected.
- The shunt field is connected across the ideal generated EMF.
- Field resistance is treated as constant.
- Self-excitation, saturation, voltage drops, load behavior, losses and ratings are excluded.
Flux is an independent selected input and is not solved from the calculated shunt current.
Selected field, rotating armature and shunt branch
The armature and commutator rotate together between the pole surfaces while the brushes and field winding remain stationary. In the shunt connection, the field winding and its series resistance form a branch across the brushes. The lower circuit diagram shows that connection separately from the machine view. Flux is an independent selected input; the calculation does not solve the field’s own excitation.
What the calculator determines
Select machine constant, flux, speed and shunt resistance. The calculator reports ideal generated EMF, corresponding shunt current and field power, plus speed in revolutions per second.
Selected steady-state algebra
E = kΦ(N/60); If = E/Rf; Pf = EIf = E²/Rf.
Selected-input arithmetic
For k = 500, Φ = 20 mWb, N = 1500 rpm and Rf = 125 Ω, ideal EMF is 250 V, shunt current is 2 A and field power is 500 W.
Reference only
The model excludes residual magnetism, field build-up, the magnetization curve, saturation, armature resistance and reaction, brush drop, load current, regulation, losses, heating, commutation and ratings.
Questions
Is flux solved from shunt current?
No. Flux is independently selected.
Is terminal voltage under load predicted?
No.
References & Further Reading
Gardner D. Hiscox, Mechanical Movements, Powers, Devices and Appliances (1901), page 189, figures 705–706: shunt generator and field connections.
- Wikipedia contributors. DC generator. Wikipedia
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