Electric motorization system with a preheating function for protecting the motor thereof against the condensation

Patent metadata

Field	Value
Publication number	US-12101049-B2
Application number	US-202017135357-A
Country	US
Kind code	B2
Filing date	Dec 28, 2020
Priority date	Dec 27, 2019
Publication date	Sep 24, 2024
Grant date	Sep 24, 2024

Abstract

An electric motorization system includes a motorized unit equipped with a motor provided with a rotor and stator assembly including several coils, and a frequency converter which is electrically powered by a power supply. The frequency converter is controlled by a monitoring/control unit for turning on the motor in a variable speed operating mode, or for turning off the motor. The electric motorization also includes a measurement system suitable for measuring at least one condensation parameter which is representative of a condensation of the water contained in an ambient air, and the monitoring/control unit is configured to, depending on said condensation parameter, control the frequency converter during the turning off of the motor so that a preheating electric current flows through the coils to activate a preheating of the motor when it is turned off.

First claim

The invention claimed is:

1. An electric motorization system comprising:
a motorized unit equipped with a motor provided with a rotor and stator assembly including several coils, and a frequency converter electrically powered by a power supply, the motor driven in rotational speed by the frequency converter which powers the coils of the motor with a variable frequency electric current;
a monitoring/control unit configured to control the frequency converter for turning on the motor in a variable speed operating mode, or for turning off the motor; and
a measurement system configured to measure at least one condensation parameter representative of a condensation of water contained in an ambient air,
wherein the monitoring/control unit is connected to the measurement system and is configured to, depending on the condensation parameter, control the frequency converter during the turning off of the motor so that a preheating electric current flows through the coils to activate a preheating of the motor when the motor is turned off, and
wherein the motorized unit comprises a motor brake configurable between an open configuration during the turning on of the motor to enable a rotation of the motor and a closed configuration blocking the rotation of the motor when the motor is turned off, whether or not the preheating is activated.

2. The electric motorization system according to claim 1 , wherein the preheating electric current is of lower value compared to the variable frequency electric current during the turning on of the motor.

3. The electric motorization system according to claim 1 , wherein the measurement system comprises a temperature measuring apparatus configured to measure a temperature of the ambient air, wherein the at least one condensation parameter includes the temperature, and the monitoring/control unit is configured to implement the preheating of the motor when the temperature is less than or equal to a dew point temperature.

4. The electric motorization system according to claim 1 , wherein the measurement system comprises a pressure measuring apparatus configured to measure a pressure of the ambient air, wherein the at least one condensation parameter includes the pressure, and the monitoring/control unit is configured to implement the preheating of the motor when the pressure is greater than or equal to a saturated vapor pressure.

5. The electric motorization system according to claim 1 , wherein the measurement system comprises a humidity measuring apparatus configured to measure a humidity content in the ambient air, wherein the at least one condensation parameter includes the humidity content, and the monitoring/control unit is configured to implement the preheating of the motor when the humidity content is greater than or equal to a predefined threshold.

6. The electric motorization system according to claim 1 , wherein the monitoring/control unit is configured to stop the preheating of the motor during the turning on of the motor.

7. The electric motorization system according to claim 1 , wherein the monitoring/control unit calculates a value of the preheating electric current depending on the at least one condensation parameter and depending on characteristic parameters of the coils.

8. A lifting crane comprising:
at least one electric motorization system according to claim 1 ; and
at least one movable member,
wherein the motorized unit of the electric motorization system is connected to the at least one movable member of the lifting crane to actuate displacement of the at least one movable member and to effect a crane maneuver when the motor is turned on.

9. The lifting crane according to claim 8 , comprising several motorized units connected to respective movable members to actuate respective displacements of the movable members and to effect respective crane maneuvers, wherein the monitoring/control unit is common to all motorized units.

10. A method for protecting against the condensation in a motor of an electric motorization system, wherein the electric motorization system comprises:
a motorized unit equipped with the motor, the motor provided with a rotor and stator assembly including several coils, and a frequency converter which is electrically powered by a power supply, the motor driven in rotational speed by the frequency converter which powers the coils of the motor with a variable frequency electric current; and
a monitoring/control unit configured to control the frequency converter for turning on the motor in a variable speed operating mode, or for turning off the motor,
wherein the motorized unit comprises a motor brake which is connected to the monitoring/control unit and configurable between an open configuration during the turning on of the motor to enable a rotation of the motor and a closed configuration blocking the rotation of the motor when the motor is turned off, the method comprising:
measuring at least one condensation parameter representative of a condensation of the water contained in ambient air;
controlling, by the monitoring/control unit, the frequency converter depending on the at least one condensation parameter, during the turning off of the motor, so that a preheating electric current flows through the coils for a preheating of the motor when the motor is turned off; and
controlling, by the monitoring/control unit, the motor brake in the open configuration during the turning on of the motor, and in the closed configuration when the motor is turned off, whether or not the preheating is activated.

11. The protection method according to claim 10 , wherein the protection method is implemented for an electric motorization system of a lifting crane, the electric motorization system connected to at least one movable member of the lifting crane to actuate displacement of the movable member and to effect a crane maneuver when the motor is turned on.

12. An electric motorization system comprising:
a motorized unit equipped with a motor provided with a rotor and stator assembly including several coils, and a frequency converter electrically powered by a power supply, the motor driven in rotational speed by the frequency converter which powers the coils of the motor with a variable frequency electric current;
a monitoring/control unit configured to control the frequency converter for turning on the motor in a variable speed operating mode, or for turning off the motor; and
a measurement system configured to measure at least one condensation parameter representative of a condensation of water contained in an ambient air,
wherein the monitoring/control unit is connected to the measurement system and is configured to, depending on the condensation parameter, control the frequency converter during the turning off of the motor so that a preheating electric current flows through the coils to activate a preheating of the motor when the motor is turned off, and
wherein the motorized unit comprises a motor brake configurable between an open configuration during the turning on of the motor to enable a rotation of the motor and a closed configuration mechanically blocking the rotation of the motor when the motor is turned off, whether or not the preheating is activated.

Assignees

• Manitowoc Crane Group France

Inventors

• Largy Frédéric

Classifications

• B66C23/022

  Pivot axis common with column · CPC title

• B66C13/22

  for electric drives (transmitting control pulses B66C13/40; systems or devices of general application H02P) · CPC title

• H02P23/14

  Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage · CPC title

• H02K11/25

  Devices for sensing temperature, or actuated thereby · CPC title

• H02K11/20

  for measuring, monitoring, testing, protecting or switching (rectifiers H02K11/04; power electronics H02K11/33) · CPC title