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A braking chopper is an magnetical switch that limits the DC bus voltage by switching the braking energy to a resistor where the braking energy is converted to heat. Braking choppers are automatically activated when the actual DC bus voltage exceeds a specified level depending on the nominal voltage of the variable-frequency drive
Schematic of an inverter using a vibrator as a chopper. In electronics, a chopper circuit is any of numerous types of electronic switching devices and circuits used in power control and signal applications. A chopper is a device that converts fixed DC input to a variable DC output voltage directly.
A DC injection brake system can be used as an alternative or addition to a friction brake system. DC injection brakes only require a small module located with the other motor switchgear and/or drivers, mounted in a remote and convenient location, whereas a friction brake must be mounted somewhere on the rotating system.
Figure 1. Diagram of piezo inchworm motor in action. Figure 2. Six-step actuation process of the piezo inchworm motor. In its simplest form, the inchworm motor uses three piezo-actuators (2 and 3, see Figure 1.) mounted inside a tube (1) and electrified in sequence to grip a shaft (4) which is then moved in a linear direction.
When the brake pipe and car components are charged with air, the brakes release. When the engineer needs to make a brake application, control valves in the locomotive reduce the brake pipe pressure. As the brake pipe pressure is reduced, the service portions on each car divert air from their reservoirs to their brake cylinders.
The circle diagram can be drawn for alternators, synchronous motors, transformers, induction motors. The Heyland diagram is an approximate representation of a circle diagram applied to induction motors, which assumes that stator input voltage, rotor resistance and rotor reactance are constant and stator resistance and core loss are zero.
In vector control, an AC induction or synchronous motor is controlled under all operating conditions like a separately excited DC motor. [21] That is, the AC motor behaves like a DC motor in which the field flux linkage and armature flux linkage created by the respective field and armature (or torque component) currents are orthogonally aligned such that, when torque is controlled, the field ...
Schematic symbol of a slip ring motor. A wound-rotor motor, also known as slip ring-rotor motor, is a type of induction motor where the rotor windings are connected through slip rings to external resistance.