supply ac brushless servo motor, dc

What is Worm Gear Motor

A worm gear assembly resembles a single threaded screw that turns a modified spur gear with slightly angled and curved teeth. Worm Gear reduction motors may be fitted with either a right-, left-hand, or hollow output (drive) shaft. This correct angle gearing kind is utilized when a sizable speed reduction or perhaps a big torque improve is needed inside a restricted quantity of space. Figure 1 shows a single thread (or single begin) worm along with a forty tooth worm gear resulting inside a 40:1 ratio. The ratio is equal towards the quantity of gear teeth divided by the amount of starts/threads around the worm. A comparable spur gear set having a ratio of 40:1 would need a minimum of two stages of gearing. Worm gears can attain ratios of much more than 300:1.

Worm gears have an inherent design advantage over other gear sets; the worm can easily turn the dc worm gear motor, but the gear cannot turn the worm. In lifting applications, this feature acts as a secondary brake due to limited back drivability.

Worms can be made with multiple threads/starts as shown in Figure 2. The pitch of the thread remains constant while the lead of the thread increases. In these examples, the ratios relate to 40:1, 20:1, and 13.333:1 respectively.

Worm gear sets can be self-locking: the worm can drive the gear, but due to the inherent friction the gear cannot turn (back-drive) the worm. Typically only in ratios above 30:1. This self-locking action is reduced with wear, and should never be used as the primary braking mechanism of the application.

27RPM DC24V 2.45NM Turbo Worm Gear Motor GW31ZY DIY Robot


1.Every product has a unique Manufacturing Part Number label on the inner package that proves it has been qualified,which include Part Number,Model Number and inspection date information;
2.If you have any questions about the item,please provide us the Manufacturing Part Number for checking,your profits will be guaranteed.
3.Use for labeling machines, remote control curtains, automatic voltage electricity, grills, ovens, washing machines, garbage disposal machines, household appliances, slot machines, the banknote recognition, automatic actuator, coffee machine, towel disposal, lighting, etc.
4.Low speed structure,high power,large output torque,stable performance,small installation space and self lock,etc.
5.This type is low speed Worm Gear DC Motor,self locking.
6.Widely used in various of occasions that require special install size.

The worm gear is usually bronze and the worm is steel, or hardened steel. The bronze component is designed to wear out before the worm because it is easier to replace.

The hoist motor can transmit motion through the gear reducer, but the load cannot transmit motion back through the gear reducer.

Regulates the lowering speed of the load
The load will not be allowed to free fall
OSHA [1910.179] recognizes this as an approved means of controlled braking

In an industry where ‘load brakes’ and ‘regenerative braking’ are widely accepted, Electrolift offers the better option by using a worm drive gearbox as the secondary braking function.

The main advantages of Electrolift’s non-load brake worm drive gear reducer:

Constant load on the load block. Load brake hoists are prohibited from doing this because it does not allow the load brake to release causing overheating and premature failure.
Long lifts – Long lifts cause load brakes to overheat and prematurely fail
Faster lifting speeds – Load brakes accumulate excessive heat as lifting speeds increase.
Inherently safe – Worm drives do not need controls or high maintenance mechanisms to ensure safe lifts.
Low Maintenance – Less moving parts than gearboxes that require complex load brake mechanisms


Stepper Motor Interfacing

Stepper motors can be used in various areas of your microcontroller projects such as making robots, robotic arm, automatic door lock system etc. This tutorial will explain you construction of Nema 42 stepper motor (unipolar and bipolar stepper motors ), basic pricipal, different controlling types (Half step and Full step), Interfacing Techniques (using L293D or ULN2003) and programming your microcontroller in C and assembly to control stepper motor.

Types of Stepper Motors

There are basic two types of stepper motors available in market.

Unipolar stepper motor

The unipolar stepper motor has five or six wires and four coils (actually two coils divided by center connections on each coil). The center connections of the coils are tied together and used as the power connection. They are called unipolar steppers because power always comes in on this one pole.
Bipolar stepper motor

The bipolar Linear Stepper Motor usually has four wires coming out of it. Unlike unipolar steppers, bipolar steppers have no common center connection. They have two independent sets of coils instead. You can distinguish them from unipolar steppers by measuring the resistance between the wires. You should find two pairs of wires with equal resistance. If you’ve got the leads of your meter connected to two wires that are not connected (i.e. not attached to the same coil), you should see infinite resistance (or no continuity).

As already said, we will talk mostly on ”Unipolar stepper motors” which is most common type of stepper motor available in the market.A simple example of 6 lead step motor is given below and in 5 lead step motor wire 5 and 6 are joined together to make 1 wire as common.

Unipolar versus bipolar stepper motor interface

There are three common types of stepper motor interfacing: universal, unipolar, and bipolar. They can be identified by the number of connections to the motor. A universal stepper motor has eight, while the unipolar has six and the bipolar has four. The universal stepper motor can be configured for all three modes, while the unipolar can be either unipolar or bipolar. Obviously the bipolar cannot be configured for universal nor unipolar mode. Table 17-7 shows selected stepper motor characteristics. Figure 17-10 shows the basic internal connections of all three type of configurations.

Unipolar stepper motors can be controlled using the basic interfacing shown in Figure 17-11, whereas the bipolar stepper requires H-Bridge circuitry. Bipolar stepper motors require a higher operational current than the unipolar; the advantage of this is a higher holding torque.

Interfacing Diagram

The diagram below shows the interfacing of stepper motor to a micro-controller. This is general diagram and can be applied to any micro-controller family like PIC micro-controller, AVR or 8051 micro-controller.


Since, the micro-controller cannot provide enough current to run the motor, a driver like a ULN2003 is used to drive the motor. Similarly, individual transistors or any other driver IC can also be used to drive the motor. See to it that if required, the external pull up resistors is connected to pins depending on the micro-controller you use. The motor must never be directly connected to the controller pins. The motor Voltage depends on the size of the motor. A typical 4 phase uni-polar stepper motor has 5 terminals. 4 phase terminals and one common terminal of the center tap that is connected to ground.

The programming algorithm for continuous rotation in clockwise mode is given below:

Initialize the port pins used for the motor as outputs
Write a common delay program of say 500 ms
Output first sequence-0 × 09 on the pins
Call delay function
Output second sequence-0 × 0 c on the pins
Call delay function
Output third sequence-0 × 06 on the pins
Call delay function
Output fourth sequence-0 × 03 on the pins
Call delay function
Go to step 3

Simulation of The Closed Loop System

Before the closed-loop system can be simulated it is necessary to choose appropriate values for yaskawa servo motors and load parameters. Every set of parameter values will, of course, lead to a unique simulation result, but in this paper it is only possible to present results corresponding to a single set of values. Some typical set of parameter values must therefore be selected.

A type 23HS-108 motor was chosen for the simulations because it typifies small hybrid Nema 23 stepper motor. The stator windings are assumed to be excited by a 24 V, 2 A bipolar chopper drive.

Choice of the load parameters is more difficult because there really is no typical load. As a general rule, however, the load inertia will not normally greatly exceed the motor inertia and for the purpose of these simulations the total inertia will be assumed to be equal to the motor inertia. Coulomb and viscous friction in the load usually dominate the motor friction. Up to a point the performance of the closed-loop system described here improves with increasing friction because friction provides the only significant damping of overshoot. The worst-case assumption is that the load friction is zero, and in the simulations presented here the total friction is assumed to be equal to the motor friction. In any real system the overshoot is likely to be less serious than that predicted by the simulations.

The results of the simulations are displayed in graphical form with the rotor angular velocity dmpos/dt (expressed in steps/s) plotted against positional error mpos-cpos (expressed in steps). There are three important situations to consider, all of which may lead to loss of synchronization in open-loop systems: operation at a resonant rate, operation above the maximum start-stop (pull-in) rate and excessive load torque.

Loss of synchronization due to resonance is only observed in lightly damped systems, particularly if an 8-step sequence is used. Figure 3 shows the response of open-loop and closed-loop systems to a sequence of 20 steps at the resonant rate of 153 steps/s. Both systems start from rest with zero positional error. In the case of the open-loop system the positional error builds up over several steps until at the 6th step the error exceeds 4 steps and synchronization is lost. This does not happen in the closed-loop system where, in spite of oscillations of approximate amplitude ±4 steps around the command position, synchronization is maintained.

The effect of operating outside the pull-in characteristic of the motor is shown in figure 4 where a

sequence of 100 steps at a rate of 4000 steps/s is applied to a motor initially at rest. As expected this simulation demonstrates that the open-loop system loses synchronization whereas the closed-loop system settles down to a rotor velocity around 4000 steps/s, and at the end of the step sequence returns to the zero error position.

Finally, figure 5 shows the effect of applying a torque of 0.5 N (which exceeds the peak motor torque) for 10 ms. This causes rapid loss of synchronization in the open-loop system whilst the closed-loop system recovers, even from very large positional errors.

Ideally the recovery from positional error should be asymptotic (that is free from overshoot) but this is far from being the case as can be seen from figures 4 and 5. The control system itself provides no damping and correct operation relies on friction in the motor and load, and on electrical damping provided by the sequencer. In most applications load friction will provide a more rapid approach to rest than that illustrated.

It is probable that a more sophisticated control algorithm could be devised which generated additional damping. For example, the motor speed could be sensed and used in a manner similar to the tachometer in a conventional servomechanism. Unfortunately this would detract from the essential simplicity of the control algorithm described here, and would involve adjustments to suit particular motor/load combinations.

How to Select PLC for Motion Control

Almost every modern industry uses programmable logic controllers, commonly known as PLCs. These compact electronic devices enable much of the automation that is prevalent in today’s manufacturing processes. Delta PLC are utilized to get a myriad of purposes in company and business, such as every thing from climate manage systems to complex item assembly and packaging processes.

Buyers unfamiliar with PLCs and their benefits may feel overwhelmed as they begin the process of selecting and purchasing PLCs for their business or industry. This guide will offer a short overview from the history and function of PLCs, such as the programming specifications and a few important elements to help keep in thoughts whilst buying for PLCs.

The factors to consider when choosing a PLC:
Size of Memory
Compatibility to HMI

Format of PLC

You can go away using the format of Little PLC simply because the count of I/O is much less than one hundred and also you don’t have servos or analog to compete with; although, from a view of studying point and becoming that Medium Format of PLC Omron would be the business function horse you’ll make use of a Medium Format PLC having a genuine of back-plain.

Speed of PLC

The speed of PLC uses to be a main concern when planning controls but does not truly affect to controls now. Nowadays PLCs are rapid enough for the majority applications with full programs scan times usually less than 4 msec. This is the scan time needed for the PLC to seem at the service and program all the Inputs/Outputs. The Cycle Time is 4 seconds so the majorities PLCs today are glowing when think this requirement of time.

Size matters – Sizing a PLC is crucial towards the achievement of one’s project. As well little and also you might max out your I/O on modifications and additions. As well big and also you might blow your spending budget. Be sure you leave space for expansion but do not break the bank.

Count up your:

Discrete input points
Discrete output points
Analog input points
Analog output points

Communications. ALWAYS have a port available on the PLC to communicate with it from your laptop without disconnecting other devices.  With modern PLCs with multiple communications methods, there is no reason for this to happen.

Will you need remote I/O?  This can reduce installation time and troubleshooting in the long term.
Will you system utilize an HMI?  How will you communicate with it?
Will you have a way to remotely monitor it from either the office across the plant or across the country?  It is becoming a standard practice.  Personally I like Ethernet but there are many options.

Brand – I’ll be unpopular when I say this, but a PLC is a PLC when it comes to most capabilities.All of the major players such as Allen Bradley, Automation Direct, Mitsubishi,Omron, and Siemens have small, medium, and large scale PLCs. Always consider when brands the end user already is using. Things will always go smoother if the maintenance personel are already familiar with the brand of PLC you choose. Also try to choose a brand that will have good local  support for the end user if you are not in the area.


Whether buyers are looking for a replacement PLC for an existing system or are interested in automating a new process, they will likely be able to find PLCs that are appropriate for their needs on Fasttobuy. Fasttobuy’s user-friendly policies and search options allow buyers to enjoy a secure and profitable shopping experience. With their new PLCs, buyers will be able to implement time saving automation technologies for their business or industry.

The Brief Introduction of DC Servo Motor

What is the meaning of servo?

In modern usage the term servo or servo-mechanism is restricted to a feedback control system in which the controlled variable is mechanical position or time derivatives of position such as velocity and acceleration.

A servo is a device, electrical, mechanical or electro mechanical, that upon receipt of a stimulus or input, will employ feedback for velocity and/or position control, creating a closed loop.

A feedback system is a control system which tends to maintain a prescribed relationship between a controlled quantity and a reference quantity by comparing their functions and using the difference as a means of control

There are mainly two types of servo-motors

1)AC Servo motor
2)DC Servo-motor

AC servo-motors are generally preferred for low-power use. And for high-power use DC servo-motors are preferred because they operate more efficiently than comparable to AC servo motors.

Unlike large industrial motors, dc servomotors are not used for continuous energy conversion. The basic operating principle is same as other electromagnetic motors.


1.It has construction as same as dc motor. It is consist of stator and rotor and controlling parts.2.It has feedback generator for generating feedback for controlling the speed & torque.
3.It has two ports one for dc supply and other for controlled dc supply.
Field Controlled DC Servo Motor Theory:

The figure below illustrates the schematic diagram for a field controlled DC yaskawa servo driver. In this arrangement the field of DC motor is excited be the amplified error signal and armature winding is energized by a constant current source.

The field is controlled below the knee point of magnetizing saturation curve. At that portion of the curve the mmf linearly varies with excitation current. That means torque developed in the DC motor is directly proportional to the field current below the knee point of magnetizing saturation curve.

Armature Controlled DC Servo Motor Theory:

The figure below shows the schematic diagram for an armature controlled DC panasonic servo motor. Here the armature is energized by amplified error signal and field is excited by a constant current source.

The field is operated at well beyond the knee point of magnetizing saturation curve. In this portion of the curve, for huge change in magnetizing current, there is very small change in mmf in the motor field. This makes the servo motor is less sensitive to change in field current. Actually for armature controlled DC servo motor, we do not want that, the motor should response to any change ofPerformance Specifications:

DC servomotors share many performance specifications that are applicable to all types of?DC motors. To properly size a motor, these specifications must be matched according to the load requirements of the application.

Shaft speed (RPM) defines the speed at which the shaft rotates, expressed in rotations per minute (RPM). Typically, the speed provided by the manufacturer is the no-load speed of the output shaft, or the speed at which the motor’s output torque is zero.

Terminal voltage refers to the design voltage of the DC motor. Essentially the voltage determines the speed of a DC motor,and speed is controlled by raising or lowering the voltage supplied to the motor.

Torque is the rotational force generated by the motor shaft.The torque required for the motor is determined by the speed-torquecharacteristics of thevarious loads experienced in the targetapplication.

Starting torque – The torque required when starting the motor,which istypically higher than the continuous torque.
Continuous torque – The output torque capability of the motor under constant running conditions.

Some ratings of dc servo-motor available:

Shaft Speed:

Less than 1,610 rpm

1,610 to 3,187 rpm
3,187 to 4,700 rpm
4,700 to 7,090 rpm
7,090 rpm and up

Terminal Voltage:

Less than 20 VDC
20 to 50 VDC
50 to 100 VDC
100 to 180 VDC
180 VDC and up

Continuous Current: 

Less than 1 amps
1 to 4 amps 4 to 8 amps
8 to 17 amps
17 amps and up

Continuous Torque:

Less than 0.45 Nm
0.45 Nm to 1.70 Nm
1.70 Nm to 5 Nm
5 Nm to 17 Nm
17 Nm and up

Continuous Output Power:

Less than 0.4 HP
0.4 to 1 HP 1 to 2 HP
2 to 6 HP
6 HP and up


  • High output power relative to motor size and weight.Encoder determines accuracy and resolution.
  • High efficiency. It can approach 90% at light loads.High torque to inertia ratio.It can rapidly accelerate loads.
  • Has ”reserve” power. 2-3 times continuous power for short periods.
  • Has ”reserve” torque. 5-10 times rated torque for short periods.
  • Motor stays cool. Current draw proportional to load.
  • Usable high speed torque.
  • Maintains rated torque to 90% of NL RPM
  • Audibly quiet at high speeds.Resonance and vibration free operation.


  • Requires ”tuning” to stabilize feedback loop.Motor ”runs away” when something breaks. Safety circuits are required.
  • Complex. Requires encoder.Brush wear out limits life to 2,000 hrs. Service is then required.
  • Peak torque is limited to a 1% duty cycle.Motor can be damaged by sustained overload.
  • Bewildering choice of motors, encoders, and servo-drives.
  • Power supply current 10 times average to use peak torque.
  • Motor develops peak power at higher speeds. Gearing often required.
  • Poor motor cooling. Ventilated motors are easily contaminated.


DC servomotors finds its applications in various domain. Some of them are given below:

  • For very high voltage power systems, dc motors are preferred because they operate more efficiently than comparable ac servomotor.
  • It has also find its application in inkjet printers and RC helicopters.
  • To drive conveyors used in Industrial manufacturing and assembling units to pass an object from one assembly station to another.
  •  It is also used in solar tracking system.DC servomotors are widely used in robots, toy cars and other position controlled devices.
  • Widely used in radars, computers, robots, machine tools tracking system, process controllers etc.

Fasttobuy co.,ltd is a professional and experienced company which specializes in producing and researching,located in changzhou city,jiangsu province, china. Our main products are stepper motors and drivers,servo motor and drivers,gear motor and other automatic device, applied widely in printing equipment, engraving machine textile machine, computer external application equipment, medical instruments, stage light equipment, robot, CNC machine and other automatic controlling system.  Exported to United States, Canada, Germany, United Kingdom, France, Switzerland, Italy, Russia, Korea and so on more than ten countries and regions in the world.

Contorl The Motor Speed With Variable Frequency Drive

A Variable Frequency Drive (VFD), sometimes referred to as a Variable Speed Drive (VSD), is a piece of equipment that regulates the speed and rotational force of an electric motor. By controlling the speed at which your applications operate, your business can save on energy costs and significantly reduce the amount of energy being consumed.

A Delta VFD may enhance the user’s profitability by improving the process, which in turn produces a fast return on investment (ROI). Process improvements may come from better:

Speed control;
Flow control;
Pressure control;
Temperature control;
Tension control;
Torque control;
Monitoring quality; and
Acceleration/deceleration control.

Let’s examine some motor equations to understand how this works.

The governing formula for the no-load (synchronous speed) of an alternating current (ac) motor in revolutions per minute (rpm) is as follows:

rpm = (ac frequency, or Hz) x (60 sec/min) / (No. of motor pole pairs)

Since rpm are in units of minutes (rev/min), and frequency is in units of seconds (cycles/sec), seconds are converted to minutes by multiplying by 60 seconds/minute. The equation can be rewritten as:

rpm = (Hz) x (60 sec/min) / (No. of motor poles/2)

If both the denominator and numerator of the above equation are then multiplied by 2 and written without units, the equation becomes:

rpm = (Hz) x (120) / (No. of motor poles)

This really is the simplest type of the equation. The much more poles the motor has, the slower the RPM. Conversely, the fewer poles the motor has, the quicker the RPM. Also, because the electrical frequency decreases, the motor?ˉs speed (rpm) will reduce, and, as frequency increases, the motor’s speed increases.

Because it’s simpler to let electronic devices alter the frequency from the voltage coming to a motor than it’s to alter the amount of poles within the motor, vfd110b23a have gained growing recognition within the HVACR business. Numerous refrigeration, air conditioning, and heat pump compressors these days can employ electronic VFDs to differ the frequency feeding their electric motors.

VFDs function by converting the motor’s ac input to direct present (dc). In the direct present, the VFD will produce a simulated ac signal at varying frequencies (see Figure 1 above). The microprocessor controlling the VFD turns on and off the waveforms?ˉ good or unfavorable half. A greater output voltage materializes in the energy device remaining on longer. Conversely, the shorter the energy device is on, the reduce the output voltage will probably be. The switch frequency will be the speed at which the energy device switches on and off. Much more heat is generated within the energy device because the switch frequency increases, but there’s now much more resolution and smoothness within the output waveform.

As talked about earlier, motor speed is straight proportional towards the electrical frequency utilized by the motor. Consequently, by varying the frequency towards the compressor?ˉs motor, the compressor’s motor speed (and, therefore, the compressor capacity) may be controlled.

Usually, the VFD also features a backlit liquid crystal show (LCD) that shows a number of motor operational parameters which are totally programmable by the user. Solid-state devices just like the silicon controlled rectifier, triac, and insulated gate bipolar junction transistor have permitted the variable-frequency drive to turn out to be the technique of option for AC motor speed manage.

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