L datasheet, L circuit, L data sheet: STMICROELECTRONICS – 3A POWER OPERATIONAL AMPLIFIER,alldatasheet, datasheet, Datasheet search . Part Number: L, Maunfacturer: ST Microelectronics, Part Family: L1, File type: PDF, Document: Datasheet – semiconductor. STMicroelectronics L Linear – Amplifiers – Instrumentation, OP Amps, Buffer Amps parts available at LH Datasheet, LH – STMicroelectronics.
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DC motors which employ permanent magnets operate as independently energized motors. Ideally, the speed of DC motors having very low internal resistance is directly proportional to the voltage applied and is not related to their torque. The speed control described here actually happens due to the voltage drops across the internal resistance Ri of the motor. Thus we find that when such a motor is loaded, the current consumption rises resulting in an increased voltage drop across its winding which ultimately affects and drops the supply voltage significantly.
So how do we control the speed of a DC motor efficiently? The figure on the left shows one practical design using the IC L which is a power op amp designed for handling output powers up to 3 amps at a maximum voltage of 36 V, and which eminently suits the proposed datasueet.
L Datasheet(PDF) – STMicroelectronics
The circuit is reasonably balanced and further modifications are not recommended, which may possibly and easily induce a lot of instability in the design. Noise interference is checked by introducing the capacitors C1, C2, C3, and R4; however a few of these may be omitted for specific loads, which will discussed in the later part of the article.
After connecting an appropriate load DC motorthe power is switched ON.
The Ri compensator preset P1 is adjusted for stabilizing the rotations dqtasheet the connected motor to a uniform level. However, over-optimization may produce apparently uncontrollable movements. Preferably P1 is adjusted immediately after the motor starts and before its armature warms up to its normal temperatures and results in an increase in its internal resistance.
The circuit uses a dual symmetrical supply which facilitates two quadrant operation of the connected motor.
The feature becomes ideally suitable for controlling model trains where two way operations become typically desirable.
Thus here the motor is made stationary by keeping the slider arm of the pot VR1 exactly at the center and then using incrementing or decrementing motions by shifting it to the relevant directions, i.
The circuit also becomes very favorable for operating and controlling small portable DC drill dataeheet like PCB drilling machines. Here the use of 24 and higher volts becomes ddatasheet and therefore the application becomes perfectly compatible with the present design. A motor being a complex device with varying torques and back EMFs, the rotor introduces a considerable capacitance.
Also noise suppressing components tend to increase the complexity, resulting in instability of the motor movement occasional stuttering. Therefore some careful optimization techniques dafasheet essential for deriving optimum response from the circuit.
Experimenting with R4, C3 by eliminating them initially can prove useful for drill machines where the inclusion of C2 becomes quite handy. With loads having built-in noise suppressors, C2 may be excluded and R5 added for protecting the op amp against sudden differential voltage peaks.
The IC being subjected to high currents may heat up considerably and therefore should be mounted over a suitably large heatsink.
If the above design does not fulfill your requirements, you may refer to another similar circuit herewhich may further help you to understand how to control a DC motor speed. ST Microelectronics — L Datasheet.