Engee documentation

Universal Motor

Universal (or serialised) motor with electrical and torque characteristics.

universal motor

Description

The Universal Motor block simulates the electrical characteristics and torque of a universal (or serialised) motor using the following equivalent circuit:

universal motor 1

In this circuit

  • - armature winding resistance;

  • - armature inductance;

  • - resistance of the field winding;

  • - field winding inductance.

If Model parameterization is set to By equivalent circuit parameters, the equivalent circuit parameters for this model are set. The Universal Motor block calculates the motor torque as follows:

  • The magnetic field in the motor induces the following back EMF in the armature winding:

    where is the proportionality constant and is the angular velocity.

  • The mechanical power is equal to the power caused by the back EMF:

  • Engine torque:

The torque to speed relationship for the universal motor model is related to the parameters in the diagram above. If Model parameterization is set to By DC rated power, rated speed & maximum torque or By DC rated power, rated speed & electrical power, the parameters of the equivalent circuit are calculated as follows:

  • The parameter has no effect on the torque-speed dependence of the steady-state torque when using a DC source.

  • The circuit voltages are summed:

  • Solve the previous equation for and substitute this value into the equation for torque:

    The unit uses the rated speed and power to calculate the rated torque. The unit uses the values for rated torque and rated speed in the previous equation plus the corresponding electrical power to determine the values and .

If Model parameterization is set to By AC rated power, rated speed, current & electrical power then the model must include the inductive terms and . This requires RMS rated current and voltage information for the total inductance.

The block models the motor inertia and damping for all values of the Model parameterization. The output torque is:

The unit generates a positive torque acting from the mechanical ports C to R.

Thermal effects of the model

You can open thermal ports to simulate the effects of losses when converting energy to heat. To open thermal ports, select the Enable thermal port checkbox.

Ports

Conserving

# + — positive terminal
electricity

Details

A non-directional port connected to the positive terminal of the universal motor.

Program usage name

p

# - — negative terminal
electricity

Details

Non-directional port associated with the negative terminal of the universal motor.

Program usage name

n

# R — motor rotor
`rotational mechanics

Details

A mechanical non-directional port associated with the rotor of a universal motor.

Program usage name

rod_flange

# C — motor housing
`rotational mechanics

Details

A mechanical non-directional port associated with the housing of a universal motor.

Program usage name

case_flange

# Hf — field winding heat port
heat

Details

Thermal port of the field winding.

Dependencies

To use this port, select the Enable thermal port checkbox.

Program usage name

field_thermal_port

# Ha — armature winding heat port
heat

Details

Thermal port of the armature winding.

Dependencies

To use this port, select the Enable thermal port checkbox.

Program usage name

armature_thermal_port

Parameters

Electrical Torque

# Model parameterization — block parameterization
By equivalent circuit parameters | By DC rated power, rated speed & maximum torque | By DC rated power, rated speed & electrical power | By AC rated power, rated speed, current & electrical power

Details

Select one of the following block parameterization methods:

  • By equivalent circuit parameters - Set the electrical parameters for the equivalent circuit model of the motor.

  • By DC rated power, rated speed & maximum torque - set the DC power and speed parameters that the unit converts to the equivalent circuit model.

  • By DC rated power, rated speed & electrical power - set the AC rated power and speed parameters that the unit converts to a motor equivalent circuit model.

  • By AC rated power, rated speed, current & electrical power - Set the AC rated power and speed parameters that the unit converts to a motor equivalent circuit model.

Values

By equivalent circuit parameters | By DC rated power, rated speed & maximum torque | By DC rated power, rated speed & electrical power | By AC rated power, rated speed, current & electrical power
Default value

By DC rated power, rated speed & electrical power
Program usage name

parameterization
Evaluatable

No

# Total armature and field winding resistance — total resistance of armature and field winding
Ohm | GOhm | MOhm | kOhm | mOhm

Details

Total resistance of armature and field winding.

Dependencies

To use this parameter, set Model parameterization to `By equivalent circuit parameters'.

Values

Ohm | GOhm | MOhm | kOhm | mOhm
Default value

132.8 Ohm
Program usage name

R_total
Evaluatable

Yes

# Back-emf constant — counter-EMF coefficient
V/(A*rad/s)

Details

The ratio of the voltage generated by the motor to the motor speed.

Dependencies

To use this parameter, set the Model parameterization parameter to `By equivalent circuit parameters'.

Values

V/(A*rad/s)
Default value

0.1722 V/(A*rad/s)
Program usage name

emf_constant
Evaluatable

Yes

# Rated speed (at rated load) — nominal speed
rpm | deg/s | rad/s

Details

Motor rotation speed at rated mechanical power.

Dependencies

To use this parameter, set Model parameterization to By DC rated power, rated speed & maximum torque, By DC rated power, rated speed & electrical power or By AC rated power, rated speed, current & electrical power.

Values

rpm | deg/s | rad/s
Default value

6500.0 rpm
Program usage name

rated_angular_velocity
Evaluatable

Yes

# Rated load (mechanical power) — rated load
W | GW | MW | kW | mW | uW | HP_DIN

Details

The mechanical load for which the motor is designed at rated speed.

Dependencies

To use this parameter, set Model parameterization to `By DC rated power, rated speed & maximum torque', `By DC rated power, rated speed & electrical power' or `By AC rated power, rated speed, current & electrical power'.

Values

W | GW | MW | kW | mW | uW | HP_DIN
Default value

75.0 W
Program usage name

P_m_rated
Evaluatable

Yes

# Rated DC supply voltage — rated DC supply voltage
V | MV | kV | mV

Details

The voltage for which the power rating is specified.

Dependencies

To use this parameter, set Model parameterization to By DC rated power, rated speed & maximum torque or By DC rated power, rated speed & electrical power.

Values

V | MV | kV | mV
Default value

200.0 V
Program usage name

V_DC_rated
Evaluatable

Yes

# Maximum (starting) torque — maximum torque
N*m | mN*m | lbf*ft

Details

The maximum torque generated by the motor.

Dependencies

To use this parameter, set Model parameterization to By DC rated power, rated speed & maximum torque.

Values

N*m | mN*m | lbf*ft
Default value

0.39 N*m
Program usage name

max_torque
Evaluatable

Yes

# Electrical power in at rated load — electrical power at rated mechanical power
W | GW | MW | kW | mW | uW | HP_DIN

Details

The amount of electrical power consumed by the motor at rated mechanical power.

Dependencies

To use this parameter, set Model parameterization to By DC rated power, rated speed & electrical power or By AC rated power, rated speed, current & electrical power.

Values

W | GW | MW | kW | mW | uW | HP_DIN
Default value

160.0 W
Program usage name

P_e_rated
Evaluatable

Yes

# RMS rated voltage — RMS nominal voltage
V | MV | kV | mV

Details

RMS supply voltage when the motor is operating on AC mains.

Dependencies

To use this parameter, set Model parameterization to `By AC rated power, rated speed, current & electrical power'.

Values

V | MV | kV | mV
Default value

240.0 V
Program usage name

V_AC_rated
Evaluatable

Yes

# RMS current at rated load — RMS current at rated load
A | MA | kA | mA | nA | pA | uA

Details

RMS current when the motor is operating on AC mains at rated load.

Dependencies

To use this parameter, set Model parameterization to `By AC rated power, rated speed, current & electrical power'.

Values

A | MA | kA | mA | nA | pA | uA
Default value

0.8 A
Program usage name

I_AC_rated
Evaluatable

Yes

# AC frequency — AC frequency
Hz | GHz | MHz | kHz

Details

The frequency of the AC power supply.

Dependencies

To use this parameter, set Model parameterization to `By AC rated power, rated speed, current & electrical power'.

Values

Hz | GHz | MHz | kHz
Default value

50.0 Hz
Program usage name

f
Evaluatable

Yes

# Total armature and field winding inductance — total inductance of armature and field winding
H | mH | nH | uH

Details

The total inductance of the armature and field winding. If the value of this inductance is not known, set a small non-zero number.

*Note

It is possible to set the Total armature and field winding inductance to zero, but this only makes sense if the motor is controlled from a DC source.

Dependencies

To use this parameter, set Model parameterization to `By equivalent circuit parameters', `By DC rated power, rated speed & maximum torque' or `By DC rated power, rated speed & electrical power'.

Values

H | mH | nH | uH
Default value

0.525 H
Program usage name

L_total
Evaluatable

Yes

Mechanical

# Rotor inertia — rotor inertia
g*cm^2 | kg*m^2 | lbm*ft^2 | lbm*in^2 | slug*ft^2 | slug*in^2

Details

The resistance of the rotor to a change in the rotational speed of the motor. The value can be zero.

Values

g*cm^2 | kg*m^2 | lbm*ft^2 | lbm*in^2 | slug*ft^2 | slug*in^2
Default value

2e-4 kg*m^2
Program usage name

J
Evaluatable

Yes

# Rotor damping — rotor energy dissipation
N*m/(rad/s) | ft*lbf/(rad/s)

Details

Energy dissipated by the rotor. The value can be zero.

Values

N*m/(rad/s) | ft*lbf/(rad/s)
Default value

1e-6 N*m/(rad/s)
Program usage name

damping
Evaluatable

Yes

# Initial rotor speed — initial rotation speed
rpm | deg/s | rad/s

Details

Rotor rotation speed at the beginning of the simulation.

Values

rpm | deg/s | rad/s
Default value

0.0 rpm
Program usage name

angular_velocity_start
Evaluatable

Yes

Temperature Dependence

# Field to armature resistance ratio, Rf/Ra — resistance ratio of the field winding and armature winding

Details

The resistance ratio of the field winding to the armature winding. This parameter is only required when using armature and field winding thermal ports. It is used to determine the individual resistance values for the field and armature windings in order to properly distribute the heat generated by the two resistors.

Dependencies

To use this parameter, select the Enable thermal port checkbox.

Default value

1.0
Program usage name

resistance_ratio
Evaluatable

Yes

# Resistance temperature coefficients, [alpha_f alpha_a] — temperature coefficients of armature and rotor resistance
1/K | 1/degR | 1/deltaK | 1/deltadegC | 1/deltadegF | 1/deltadegR

Details

A 1 by 2 line vector containing the coefficients in the equation relating resistance to temperature. The first element corresponds to the field winding and the second element corresponds to the armature winding. By default, the values for copper are used.

Dependencies

To use this parameter, select the Enable thermal port checkbox.

Values

1/K | 1/degR | 1/deltaK | 1/deltadegC | 1/deltadegF | 1/deltadegR
Default value

[3.93e-3, 3.93e-3] 1/K
Program usage name

alpha_vector
Evaluatable

Yes

# Measurement temperature — measuring temperature
K | degC | degF | degR | deltaK | deltadegC | deltadegF | deltadegR

Details

The temperature for which the motor parameters are determined.

Dependencies

To use this parameter, select the Enable thermal port checkbox.

Values

K | degC | degF | degR | deltaK | deltadegC | deltadegF | deltadegR
Default value

25.0 degC
Program usage name

T_measurement
Evaluatable

Yes

Thermal Port

# Enable thermal port — switching on the thermal ports

Details

Modelling of thermal effects.

To enable thermal effects modelling, set the parameter checkbox to `enabled'.

Default value

false (switched off)
Program usage name

has_thermal_port
Evaluatable

No

# Thermal masses, [Mf Ma] — thermal masses
J/K | kJ/K

Details

A 1 by 2 line vector containing thermal mass values for the field and armature windings.

Thermal mass is the energy required to raise the temperature by one degree.

Dependencies

To use this parameter, select the Enable thermal port checkbox.

Values

J/K | kJ/K
Default value

[100.0, 100.0] J/K
Program usage name

thermal_mass_vector
Evaluatable

Yes

# Initial temperatures, [T_field T_armature] — initial temperatures
K | degC | degF | degR | deltaK | deltadegC | deltadegF | deltadegR

Details

A 1 by 2 line vector containing the temperature values of the excitation and armature thermal ports at the start of the simulation.

Dependencies

To use this parameter, select the Enable thermal port checkbox.

Values

K | degC | degF | degR | deltaK | deltadegC | deltadegF | deltadegR
Default value

[25.0, 25.0] degC
Program usage name

T_vector_start
Evaluatable

Yes

Literature

Bolton, W. Mechatronics: Electronic Control Systems in Mechanical and Electrical Engineering, 3rd edition Pearson Education, 2004.