How to interpret motor drawings?

The motor performance curve is a diagram that describes the changes in key parameters of the motor under different loads, and is used to visualize the output characteristics, efficiency and working range of the motor. However, many technical engineers often encounter the following problems when looking at motor curve diagrams:

• The type of curve is unclear

• Lack of key parameter annotation

• The unit is confused or not marked

• The voltage conditions are unclear

• Lack of temperature or environmental working conditions

• The curve data is inconsistent with the actual prototype

• The allowable scope of work is not given

• Only static graphs are provided, and dynamic response is lacking

To address the above issues, you need to understand the following core elements:

Basic structure of graph

1、Horizontal axis (X-axis): usually torque (unit: Nm or Kg-cm), from left to right indicates a gradual increase in torque

2、Vertical axis (Y-axis): contains four parameters, corresponding to four curves:

• Speed shaft (in rpm): The speed decreases with the increase of torque.

• Power Shaft (in W): Change in output power.

• Efficiency axis (unit: %): The efficiency at which electrical energy is converted into mechanical energy.

• Current axis (unit: A): The increase or decrease of the input current.

In the motor curve drawing, the torque-speed curve (TN curve) is the core parameter, and its importance is reflected in the load response core and the basis for judging the adaptation of working conditions

The efficiency curve can best reflect the energy-saving potential of motors, especially for long-term operating systems such as new energy vehicles and industrial equipment

BG80:Reference Drawing

Key Extreme Points :

• Maximum efficiency point: 82.0% (corresponding torque 373.6mN·m, rotational speed 9441r/min)

• Maximum output power : 561.73W (torque 890.2mN·m, speed 6026r/min)

• Stopping Current: 25.461A (Ultimate Torque 890.2mN·m)

Core performance nodes and adaptation scenarios

1. No load condition (No_Load)

Parameter characteristics: torque 16.2mN·m, speed 11804r/min, efficiency only 15.7%

Adaptive scenarios:

• The device starts instantly

• Light load operation status (such as low fan gear)

• Precautions: The electricity is seriously wasted and should not be operated for a long time

2. Optimal efficiency point (Max_Eff)

Parameter characteristics: torque 373.6mN·m, speed 9441r/min, efficiency 82.0%

Adaptive scenarios:

• New energy vehicle drive motor cruise phase

• Continuous operation of industrial equipment (energy-saving priority scenario)

• Advantages: 0.82W of mechanical energy can be output per 1W of electrical input

3. Maximum power point (Max_Pout).

Parameter characteristics: torque 890.2mN·m, speed 6026r/min, power 561.73W

Adaptation scenario:

• Short-term overload of construction machinery (such as the moment of lifting the crane)

• Power tools drill holes with high loads

• Risk warning: The efficiency is reduced to 61.2%, and the heat dissipation design is required

4. Blocking and turning conditions (Max_Torque).

Parameter characteristics: torque 890.2mN·m, speed 0r/min, current 25.461A

Adaptation scenario:

• Servo system position hold

• Safety braking device

• Protection requirements: Overcurrent protection circuit must be configured