Wiring panel: motor

Showing posts with label motor. Show all posts

Thursday, August 15, 2013

Two Basic Motor Speed Controllers

Here are two simple 12V DC motor speed controllers that can be built for just a few dollars. They exploit the fact that the rotational speed of a DC motor is directly proportional to the mean value of its supply voltage. The first circuit shows how variable voltage speed control can be obtained via a potentiometer (VR1) and compound emitter follower (Q1 & Q2). With this arrangement, the motor’s DC voltage can be varied from 0V to about 12V. This type of circuit gives good speed control and self-regulation at medium to high speeds but very poor low-speed control and slow starts. The second circuit uses a switchmode technique to vary motor speed.

Circuit diagram:

Fig.1: a very simple motor speed controller based on a compound emitter follower (Q1 & Q2).

Here a quad NOR gate (IC1) acts as a 50Hz astable multivibrator that generates a rectangular output. The mark-space ratio of the rectangular waveform is fully variable from 20:1 to 1:20 via potentiometer VR1. The output from the multivibrator drives the base of Q1, which in turn drives Q2 and the motor. The motor’s mean supply voltage (integrated over a 50Hz period) is thus fully variable with VR1 but is applied in the form of high-energy "pulses" with peak values of about 12V.

Circuit diagram:

Fig.2: this slightly more complicated circuit gives better low speed control and higher torque.

This type of circuit gives excellent full-range speed control and gives high motor torque, even at very low speeds. Its degree of speed self-regulation is proportional to the mean value of the applied voltage. Note that for most applications, the power transistor (Q2) in both circuits will need to be mounted on an appropriate heatsink.

Source by : Streampowers

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Saturday, April 13, 2013

zBot 10 A Power Stage for DC Motor

If\r\n you take a look at the chassis of the zBot vehicle1, you’ll find two sections \r\nrequiring intelligent keep a watch on: the steerage servo and the DC motor. The \r\nso known as H-bridge is the normal circuit for electronic control of \r\nrevolution pace and route. The DC motor of a Tamiya automobile is powerful\r\n sufficient to propel zBot at as so much as 20 miles per hour.

The\r\n motor then consumes more than 10 A, so we make a selection high-current energy \r\nMOSFETs for the cause force stage. There are numerous totally different softwares to \r\nchoose from. The MOSFET we require has to provide the maximum motor \r\ncurrent and, importantly, it needs to be switched with gate voltages of \r\nabout 5 V. In this case, the microcontroller switches the ability stage \r\n(‘low aspect’) directly. For high aspect riding degree shifters are \r\nnecessary. The schematic of the H-bridge power stage presentations a few \r\ninverters, NAND gates and two tri-stateable drivers. These logic \r\nfunctions are essential as the better approach, i.e.., in an instant \r\ncontrolling all 4 MOSFET has a fatal disadvantage.

In\r\n case of a software crash it may well happen that two ore extra MOSFETs are \r\nswitched on incor-rectly for exam-ple, T4 and T7. In that case, the \r\ncurrent throughout the transistors is proscribed by using the interior resistors of \r\nthe MOSFETs (about 10 mO) simplest. Such a deadly error would destroy the \r\nMOSFETs. The common sense performs configured here successfully avoid illegal \r\nstates.To keep an eye fixed on the DC motor, three signals are needed: DIR, PWM and \r\nSTOP. DIR regulates the path of the motor revolution, PWM the rate,\r\n and STOP brakes the motor.

The\r\n software program module for the DC motor is called dcm.c.(070172-I) The \r\ncomplete document referred to as Zbot the Robot Experimental Platform is \r\navailable free of charge downloading from the Elektor Electronics site. The\r\n file quantity is 070172-11.zip (July/August 2007).

http://www.ecircuitslab.com

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Sunday, April 7, 2013

Stepper Motor Controller

Stepper motors are available in several versions and sizes with a variety of operating voltages. The advantage of this general-purpose controller is that is can be used with a wide range of operating voltages, from approximately 5 V to 18 V. It can drive the motor with a peak voltage equal to half the supply voltage, so it can easily handle stepper motors designed for voltages between 2.5 V and 9 V. The circuit can also supply motor currents up to 3.5 A, which means it can be used to drive relatively large motors. The circuit is also short-circuit proof and has built-in over temperature protection. Two signals are required for driving a stepper motor. In logical terms, they constitute a Grey code, which means they are two square-wave signals with the same frequency but a constant phase difference of 90 degrees. IC1 generates a square-wave signal with a frequency that can be set using potentiometer P1.

This frequency determines the rpm of the stepper motor. The Grey code is generated by a decimal counter in the form of a 4017. Outputs Q0–Q9 of the counter go high in succession in response to the rising edges of the clock signal. The Grey code can be generated from the outputs by using two OR gates, which are formed here using two diodes and a resistor for each gate, to produce the I and Q signals. Here ‘I’ stands for ‘in-phase’ and ‘Q’ for ‘quadrature’, which means it has a 90-degree phase offset from the I signal. It is common practice to drive the windings of a stepper motor using a pair of push-pull circuits for each winding, which is called an ‘H bridge’.

That makes it possible to reverse the direction of the current through each winding, which is necessary for proper operation of a bipolar motor (one whose windings do not have centre taps). Of course, it can also be used to properly drive a unipolar motor (with centre-tapped windings). Instead of using a push-pull circuit of this sort, here we decided to use audio amplifier ICs (type TDA2030), even though that may sound a bit strange. In functional terms, the TDA2030 is actually a sort of power opamp. It has a difference amplifier at the input and a push-pull driver stage at the output.

Circuit diagram:

Stepper Motor Controller Circuit Diagram

IC3, IC4 and IC5 are all of this type (which is economically priced). Here IC3 and IC4 are wired as comparators. Their non-inverting inputs are driven by the previously mentioned I and Q signals, with the inverting inputs set to a potential equal to half the supply voltage. That potential is supplied by the third TDA2030. The outputs of IC3 and IC4 thus track their non-inverting inputs, and each of them drives one motor winding. The other ends of the windings are in turn connected to half the supply voltage, provided by IC5. As one end of each winding is connected to a square-wave signal that alternates between 0 V and a potential close to the supply voltage, while the other end is at half the supply voltage, a voltage equal to half the supply voltage is always applied to each winding, but it alternates in polarity according to the states of the I and Q signals.

That’s exactly what we want for driving a bipolar stepper motor. The rpm can be varied using potentiometer P1, but the actual speed is different for each type of motor because it depends on the number of steps per revolution. The motor used in the prototype advanced by approximately 9° per step, and its speed could be adjusted over a range of approximately 2 to 10 seconds per revolution. In principle, any desired speed can be obtained by adjusting the value of C1, as long as the motor can handle it. The adjustment range of P1 can be increased by reducing the value of resistor R5. The adjustment range is 1:(1000 + R5)/R5, where R5 is given in k.If a stepper motor is switched off by removing the supply voltage from the circuit, it’s possible for the motor to continue turning a certain amount due to its own inertia or the mechanical load on the motor (flywheel effect).

It’s also possible for the position of the motor to disagree with the states of the I and Q signals when power is first applied to the circuit. As a result, the motor can sometimes ‘get confused’ when starting up, with the result that it takes a step in the wrong direction before starting to move in direction defined by the drive signals. These effects can be avoided by adding the optional switch S1 and a 1-k resistor, which can then be used to start and stop the motor. When S1 is closed, the clock signal stops but IC2 retains its output levels at that moment, so the continuous currents through the motor windings magnetically ‘lock’ the rotor in position. The TDA2030 has internal over temperature protection, so the output current will be reduced automatically if the IC becomes too hot. For that reason, it is recommended to fit IC3, IC4 and IC5 to a heat sink (possibly a shared heat sink) when a relatively high-power motor is used. The tab of the TO220 case is electrically bonded to the negative supply voltage pin, so the ICs can be attached to a shared heat sink without using insulating washers.

Source by : Streampowers

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Thursday, April 4, 2013

Phase Synchronous Motor Wiring Diagramcircuit Schematic

Phase Wiring on Correct Wiring For Three Phase By Helmuth

Correct Wiring For Three Phase By Helmuth.

Phase Wiring on This Three Phase Power System Is Called Three Phase Star

This Three Phase Power System Is Called Three Phase Star.

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Phase Motor Contactor Wiring Diagram.

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Some Basic Facts About 3 Phase Motor Wiring Are.

Phase Wiring on Figure 1a Wiring Diagram Of Three Phase Motor

Figure 1a Wiring Diagram Of Three Phase Motor.

Phase Wiring on 240 480 High Leg Delta Phase To Phase 480v Phase

240 480 High Leg Delta Phase To Phase 480v Phase.

Phase Wiring on Phase Contactor Wiring Diagram

Phase Contactor Wiring Diagram.

Phase Wiring on Free Energy Fact Or Fiction Animations By Mallen7424

Free Energy Fact Or Fiction Animations By Mallen7424.

Phase Wiring on Phase Synchronous Motor Wiring Diagram Circuit Schematic

Phase Synchronous Motor Wiring Diagram Circuit Schematic.

Phase Wiring on And There You Have It Not Really Much More Difficult Than Single

And There You Have It Not Really Much More Difficult Than Single.

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