Testing AC power sources, such as uninterruptible power supplies, can be a real challenge. These products are often tested with resistive load banks, but this approach does not simulate real-world conditions such as switching DC/AC converters found in many AC powered products.
When performing functional tests, keeping test times as short as possible is often a critical requirement. Time is money, after all. One way to reduce test times is to reduce the latency in setting up signal switch paths, stimulus devices, and measurements. These can all have a significant impact on the overall time it takes to complete a full functional test of a particular DUT.
Manufacturing and test environments can be very demanding, and most manufacturers need test equipment that is both accurate and reliable to meet increasing product throughput demands. To meet these demands, AMETEK Programmable Power has introduced the VTI EX1403 16-channel bridge and strain gauge instrument. The EX1403 sets the standard for stress and fatigue testing, delivering the highest performance measurements possible while keeping overall test hardware costs low and maximizing system uptime.
AMETEK VTI's new RX0424 IEPE/Voltage Instrument is a cost-effective new device that is ideal for measuring acceleration forces and sensing static and dynamic movement or vibrations. Fully-integrated IEPE current excitation and tachometer input channels further enhance the instrument’s utility and functionality.
The RX0424’s precise signal path design delivers laboratory-grade measurements to the field. The RX4024 provides exceptional accuracy and repeatability by using independent 24-bit analog-to-digital converters at programmable data acquisition rates up to 204.8 kSa per second. Multiple input ranges help ensure that users capture all vibration events, large or small, and precision
The RX4024 connects directly to Integrated Electronic Piezoelectric (IEPE) transducers, which have a built-in charge amplifier or voltage amplifier. IEPE current excitation sources can be programmed to supply either 4.5 mA or 10 mA drive current. These sources can also be tailored to specific application demands.
In Part I, we introduced you to the concept of testing equipment for immunity to voltage dips and short power interruptions in accordance with IEC 61000-4-111. In addition to specifying the test waveforms, the standard also specifies AC source requirements for full compliance testing.
Mains voltage dips and short interruptions can be caused by a wide variety of phenomena and can cause equipment to operate unreliability, and in some cases, can damage the equipment. Faulty loads on an adjacent branch circuit, for example, can cause a circuit breaker to trip, and high-power loads such as welders, motors and electric heaters can cause voltage variations. Natural events, such as power lines downed by storms or lightning strikes, may also disrupt mains power.
While switch-mode power supplies have many advantages, one of their disadvantages is that they are a non-linear load, and because of that can inject harmonic currents into the electrical distribution system. Devices with switching supplies include domestic appliances (TVs, microwave ovens, lighting equipment and dimmers), and office equipment (PCs, printers). Motor-driven equipment can also cause harmonic distortion.