Electrical machines and transformers
DC motors, induction motors (slip, Kloss equation) and transformers: ratio, short circuit, part-load efficiency and voltage regulation.
Enter nameplate data, determine the operating point and cross-check with the manufacturer's curves or test report.
Calculators in this category
DC motor starting resistor
Calculate series resistance needed to limit initial armature current of a stationary DC motor.
Open calculator →Induction motor slip
Evaluate synchronous speed and relative slip of an induction motor from frequency, pole pairs and rotor speed.
Open calculator →Transformer short-circuit current
Estimate prospective steady short-circuit current from rated current and relative impedance established by the short-circuit test.
Open calculator →Transformer partial-load efficiency
Determine transformer efficiency at a specified load from rated apparent power, power factor and test losses.
Open calculator →DC motor back EMF
Determine induced back EMF and converted electromagnetic power of a running DC motor from armature-circuit data.
Open calculator →DC motor overall efficiency
Determine shaft output power and overall efficiency of a DC motor from armature-circuit data and mechanical loss power.
Open calculator →Transformer no-load current ratio
Determine a transformer's no-load current relative to its rated current from the no-load test.
Open calculator →Induction motor torque ratio (Kloss equation)
Calculate the ratio of internal torque to breakdown torque of an induction motor at given slip and breakdown slip using the Kloss approximation.
Open calculator →Transformer relative voltage change under load
Estimate a transformer's relative secondary voltage change at rated load from the per-unit short-circuit voltage components and power factor.
Open calculator →Transformer turns ratio
Calculate secondary voltage or turns ratio of an ideal transformer.
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