Tag: difference between

The solenoid valve is one of the products for fluid control automation. According to the start-up working model of the solenoid valve, it can be divided into the most frequently-used two categories: pilot-operated solenoid valve and direct acting solenoid valve. However, if not choose the right one, it easily causes the solenoid valve does not work. Meanwhile, it will somewhat affect the safety of the application. Then, how to distinguish the difference between pilot-operated and direct acting solenoid valve? How to choose the right one for the better application? The following will give you some enlightenment.

Circuit breakers and fuses can protect the electric equipment and lines from short circuit. Actually, both have their own characteristics. Circuit breakers are used to switch on and off the load circuit as well as cut off the fault circuit, so as to ensure the safety. The fuse is used as a protector by melting itself when the current is too high or exceeds the load current. It is completely different from the circuit breaker on the breaking current. Its function can be easily understood by the commonly used fuse in our home.

AC motors are divided into two types, synchronous motors and asynchronous motors which are also called induction motors. The biggest difference between synchronous motors and asynchronous motors (induction motors) is whether the speed of rotor is consistent with the speed of the rotating magnetic field in the stator. If the rotor’s rotation speed and the stator’s field speed are the same, it is called synchronous motor; if not, it is asynchronous motor. Furthermore, there are big differences specific to the performance parameters and applications between the two.

DC motors are mainly divided into brushless DC motors and brushed DC motors.
Brushed DC motor
DC motor is famous for its good start-up performance and speed performance, in which brushed DC motors use mechanical commutator to make driving simple, see the model diagram shown in Figure 1.
The motor is mainly composed of a stator made of permanent magnetic material, a rotor (armature) wound with a coil winding, a commutator and a brush. As long as the brush A and B at both ends of a certain direct current, the motor commutator will automatically change the direction of the motor rotor magnetic field, so that DC motor rotor will continue to run.

A contactor is mainly used in a primary loop, which can go through a large current (several hundred to about one thousand Amps). While a relay is used in a secondary circuit to achieve various control functions, which can only go through a small current (several to decades Amps). Functions, contacts opening and closing situation of the two subject are different.

Solid state relay (SSR) is a non-contact switch composed of solid-state electronic components with high reliability, non-contact, no spark, long life, no noise, no electromagnetic interference, high switching speed. Electromechanical relays (EMR) is a kind of magnetic switch made up of multi-coils, movable elements, contact system etc. and it is easy to drive and widely used in all the areas. Then what are they differences? Which one is better?

Stepper motors is used in open-loop control, thus it is simple, low cost and can be widely used. However, the open-loop control of the stepper motor cannot avoid the inherent disadvantages of the stepper motor itself, that is, resonance, oscillation, step loss and difficult to achieve high speed. Correspondingly, the closed-loop control of stepper motor can make up these shortcomings, and have the advantages of open-loop drive and brushless DC servo motor.