Motor Control Circuits
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Microchip Technology (www.microchip.com) offers a family of cooling-fan speed controllers that operate in PWM mode for use with brushless dc fans (Reference 1). To control fan speed using the PWM waveform`s duty cycle, you can use either an external NTC....
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The circuit is not particularly susceptible to motor transients and supports FULL STEPS FORWARD, FULL STEPS REVERSE, ACTIVE HOLD, and POWER OFF aka RELEASED. If the motor does not turn then swap around the leads of ONE of the two coils. To reverse the sense....
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Like most other ESCs, this one is built up using N-channel Power MOSFET`s because of their good characteristics (low DS resistance). Since this ESC has no reverse, it is not meant to be used in R/C cars or boats if reversed motor run is needed. It is more....
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The first servo controller project at http://www.rentron.com/servo.htm had the com port fixed at com1. This new version will seek out the available com ports on your PC and then let you select the desired port and baud rates. It has 1 additional servo port....
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This page shows some methods of track routing control for Stall-Motor type switch machines. The principle method uses a 2 Pole - Multi Position rotary switch while an alternate uses optoisolators and transistors to select the routes. The last circuits on....
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This 555 timer based PWM controller features almost 0..100% pulse width regulation using R1, while keeping the oscillator frequency relatively stable. The frequency is dependent on values of R1 and C1, values shown will give a frequency range from about 170....
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The circuit in Figure 1 is a simple, economic, compact, and tricky way of using the LM723 as a programmable voltage source to drive dc micromotors. Because of the µPs` accurate positioning and control, these motors are useful in applications such as optical....
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The purpose of a motor speed controller is to take a signal representing the demanded speed, and to drive a motor at that speed. The controller may or may not actually measure the speed of the motor. If it does, it is called a Feedback Speed Controller or....
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A simple, time-honored approach is to use one or more 74*245 chips (normally the 74AC245 is used for maximum current capability) to provide motor drive current. Here, each channel of drive power is provided by one or more buffer on the chip...
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Speed controllers have long exploited the reverse-EMF characteristics of dc motors to control their speed. These linear driver circuits use power op amps to create a negative resistance drive to the motor that counteracts the voltage drop in the motor`s....
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Figure 1 shows how to position a mechanical device into four discrete positions but with only two free outputs and one free input from the control system. The position depends on a set of cams and four corresponding limit switches. The 24V-dc motor comes....
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Two inputs, A and B, control the bridge. With both high (or open circuit) both ends of the motor are connected to 0v. Connect A low and Tr2 turns on causing the motor to go forward. Connect B low and Tr6 turns on, reversing the motor. If A and B are both....
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This page features H-Bridge circuits used for controlling direct current motors. Several designs are shown using both CMOS and Bi-Polar power devices. These circuits could be used as the basis for Model Railroad DCC Boosters or PWM motor controllers. The....
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This is a circuit for controlling the speed of small DC motors, it works nicely as a speed controller for an HO or N gauge model railroad...
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A pulse width modulator (PWM) is a device that may be used as an efficient light dimmer or DC motor speed controller. The circuit described here is for a general purpose device that can control DC devices which draw up to a few amps of current. The circuit....
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These two schematics are variations on another PWM circuit that I designed. The diagrams are for 12V operation only and there are high side (common ground) and low side (common +12V) versions. The low side version of the circuit uses an N Channel FET, the....
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This DC Motor Controller circuit will control a 12V dc motor. The system will have three pushbuttons: a START button, a REVERSE button and a STOP button. Initially, the motor must not be running. When the START button is pressed, the motor will run in one....
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You will find this identical circuit inside most 3 wire computer fans with speed monitoring output to the motherboard. Peel off the sticker from the fan hub in order to access a motor winding pin for connecting up the tacho circuit...
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The heart of the Chloroplast is the Motorola MC34164-3 Micro power Undervoltage Sensing Circuit (U1 in the following diagram). In normal use, this component monitors the voltage at pin 2, and applies a ground at pin 1 ( out ) when the monitored voltage drops....
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Figure 2 is a diagram of the control circuit
built on a 1.45 X 1.8 inch PC board. IC1 is
an LMC555 CMOS timer that generates a
200 microsecond wide clock pulses to step
the motor and control its speed. The speed
can be varied by changing the pulse....
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An electronic speed control for an AC Motor can be
designed with a Light Dimmer IC by limiting the minimum
firing angle of the triac so that the motor wont
stall. This can be done effectively for high volume applications
by making a minor change to the....
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This application note describes how to implement a compact size and high-speed
interrupt driven step motor controller. Step motors are typically used in applications
like camera zoom/film feeder, fax machines, printers, copying machines, paper feeders/....
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Battery run times for notebook computers and other
portable devices can be improved and acoustic noise
reduced by using Linear Technologys LTC®1695 to optimize
the operation of these products internal cooling
fans. The LTC1695 comes in a SOT-23 package....
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Figure 1 shows a block diagram for a fan speed control
system using the LTC1840. The LTC1840 contains two
current DACs used to gain full control over fan speed. The
scaled currents individually adjust the fan-driving output
voltage of a switching....
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The controller is a prototype and works well in my plane with 7 cells and a Graupner-Speed 600...
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For normal use it`s necessary to connect the battery, when the jumper is connected.
Please take care, that the transmitter is on and the throttle is set to "power off"...
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Controller for brushless
and sensorless motors, with active rpm control # Active rpm control
# Car mode
# Proportional brake
# Active freeweehling
# Updates via Internet available..
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No description available...
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If the transmitter stick-potentiometer delivers a voltage about 2 - 3 V, this circuit will be suitable. If you want to avoid using the battery cable (supplying Vcc for IC1and -2), you can use a separate 5V supply for IC1 and -2. In that case you should test....
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The controller uses one or more ordinary silicon diodes as a sensor, and uses a cheap opamp as the amplifier. I designed this circuit to use 12V computer fans, as these are now very easy to get cheaply. These fans typically draw about 200mA when running, so....
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This hybrid circuit uses a mixture of transistors, an IC and a relay and is used to automatically open or close a pair of curtains. Using switch S3 also allows manual control, allowing for curtains to be left only partially open or closed. The circuit....
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The circuit described here is for a general purpose device that can control DC devices which draw up to a few amps of current. The circuit may be used in either 12 or 24 Volt systems with only a few minor wiring changes. This device has been used to control....