HPV 900
Motor Parameter
Calculation
from the motor’s equivalent circuit
The document details how to calculate the following HPV 900 motor parameters, which
are entered as a percentage of the base impedance:
• Stator Leakage Reactance (STATOR LEAKAGE X)
• Rotor Leakage Reactance (ROTOR LEAKAGE X)
• Stator Resistance (STATOR RESIST)
Also,
• Motor Iron Loss (MOTOR IRON LOSS)
• Motor Mechanical Loss (MOTOR MECH LOSS)
• Initial value for Percentage No Load Current (% NO LOAD CURR)
The following data is required:
• Rated motor power in KW (or HP)
• Rated motor frequency (f)
• Rated motor current (Irated)
• Rated motor line-to-line voltage (Vl-l)
• Equivalent single-phase circuit of the motor
Rs
Vl-l
Lr
Ls
Lm
Rfe
3
Rr
slip
Rs, Rfe, Rr in ohms
Ls, Lm, Lr in henry
Equivalent single-phase circuit of the motor
(Y connected)
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HPV 900 Motor Parameter Calculation
Calculate Zbase (base impedance)
Zbase
=
Vl 2− l
power (in kW) × 1000
note:
KW = HP × 0.746
Calculate Rs (stator resistance)
as a percentage of the base impedance
Rs (%) =
Rs
(in ohms)
× 100
Zbase
note:
Rs is per phase (Y connected)
Calculate Ls (stator reactance)
as a percentage of the base impedance
Ls (%) =
2πf × Ls
(in henry)
Zbase
× 100
note:
if XLs are available then do not use (2πf)
Ls is per phase (Y connected)
Calculate Lr (rotor reactance)
as a percentage of the base impedance
Lr (%) =
2πf × Lr
(in henry)
Zbase
× 100
note:
if XLr are available then do not use (2πf)
Lr is per phase (Y connected)
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HPV 900 Motor Parameter Calculation
Calculate Motor Iron Loss
as a percentage of the motor’s rated power
1
R fe (in ohms)
total iron loss (in kW)
× 100 =
× 100
power (in KW) × 1000
power (in KW) × 1000
Vl 2− l ×
% Iron Loss =
note:
KW = HP × 0.746
Rfe is per phase (Y connected)
Calculate Motor Mechanical Loss
as a percentage of the motor’s rated power
% Mechanical Loss =
total loss (in kW)
× 100
power (in KW) × 1000
note:
KW = HP × 0.746
Calculate Percentage No Load Current
as a percentage of the motor’s rated current
% no load current
=
 Vl − l

 3





2πf × Lm × I rated
note:
if XLm are available then do not use (2πf)
Lm is per phase (Y connected)
After this initial value is entered, use the adaptive tune procedure
to properly tune.
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