By Steve Meyer || A major hardware cost in control systems is that for inputs and outputs. Devising the most suitable arrangement of I/O takes creation of an I/O map. Then grouping I/Os by location helps engineers identify packaging needed to deploy hardware correctly. One caveat: Unless one is using new breeds of design software, mapping and […]
FAQs + basics
FAQ: Why are DC motor armature cores made of laminations?
DC motors are constructed with two major parts: the rotor and the stator. The rotor has a ring-shaped iron core with slots that hold coils, or windings. Following Farady’s law, when the core is rotated in a magnetic field, a voltage, or EMF, is induced in the coils. This induced EMF causes current to flow, […]
FAQ: What’s the favored network for PLCs, Ethernet or fieldbus options?
The obvious or trite answer is; it depends. It depends on the needs of the application such as speed, timing, number of I/O, etc. But there’s also the notion that what PLC you happen to be using will dictate the choice of network. So, a Rockwell PLC would be Ethernet/IP or DeviceNET, Siemens would be […]
FAQ: How do stepper drives and motors get smooth motion and consistent torque at low speed?
Smooth operation at low speeds with consistent torque is possible using stepper motors and drives. It is accomplished by ensuring the drive and motor work together, and often by using microstepping. Microstepping is driving the stepper motor such that each pulse does not complete a full step. Rather, a partial step occurs. This allows the […]
FAQ: What is the Swinburne test for DC motors?
The Swinburne test is an indirect method for determining the efficiency of DC motors. It works by finding the no-load losses experimentally and then estimating additional losses from the rated motor data. From this information, the efficiency can be determined at any applied load. First, the no-load current and shunt field current are obtained directly […]
FAQ: What are rotational losses in DC motors?
DC motors, like all machines, experience some losses when converting electrical power to mechanical power. (Note that in generators, mechanical power is converted to electrical power, but the losses experienced are the same.) While there are several ways in which manufacturers and experts group losses, one common method is to divide them into five categories: mechanical, […]
7 questions to ask before picking an ac motor drive (controller) for an application
By Jeff Conner • Dallas Service Manager for Control Concepts AC motor drives (or controllers as we call them in this context) come with a range of options — including different control interfaces, enclosures, and motor-control methods. They provide flexible choices for machine designs and can leave the door open for future improvements and upgrades. Modern AC drives […]
FAQ: What is pole-damping technology in stepper drives?
Pole-damping technology refers to a unique method of microstepping employed by specially equipped stepper drives. Note that Lin Engineering trademarks the term Pole Damping, as it employs their proprietary technologies. Also do not confuse damping, which is the addition of components to a motor setup to reduce vibration and noise, with pole damping, which involves […]
What is distributed architecture for servo drives?
Article updated August 2019 || Traditional servo-system architecture consists of a power supply, a motion controller, and servo drives all housed in one location that is typically a control cabinet located away from the machine. Then each motor connects to the control cabinet by two cables … one for power and one for feedback. This […]
FAQ: What are the pros and cons of integrated stepper motor-drive combinations?
Stepper drives and motors can integrate into one unit. Manufacturers supply various combinations of integrated stepper motor-drive combinations. These integrated stepper and drive units have their advantages and drawbacks. The benefits of the integrated motor and drive units include ease of implementation, reduced wiring complexity, faster setup and construction of a system and guaranteed motor-drive […]