Hoyt's new ACA-20PC Series are the first digital ac ammeters to incorporate onboard
current transformers (CT's), and they are amazingly easy to use. Simply pass the
current-carrying load wire through the ACA-20PC's on-board CT, apply power to the meter's
two supply terminals, and you're instantly measuring ac currents over one of four ranges
(0-2A with 1mA resolution, 0-20A with 10mA resolution, or 0-50A and 0-100A with 100mA
resolution). Absolutely no external components, such as expensive low-value shunts or 5A
"donut" CT's, are required.
Meters are ac powered (120/220Vac @ 50/60Hz) or dc powered (+5-40V) and impose
minimal loads (50mA max. and 120mA max., respectively) on their supplies. All models
employ auto-zeroing circuits, precision bandgap references, and super stable thin-film
resistors for unsurpassed accuracy (±0.15%FS) and stability.
The functionally complete ACA-20PC ammeters provide all the scaling/interface
circuitry to mate the CT's output to a precision (3½ digit) A/D converter. The A/D's output
goes directly to drivers for the meters' large (0.37"/9.4mm digit height), easy-to-read, LED
displays. AC-powered units have on-board AC/DC converters, and wide-range dc-powered
units have on-board linear regulators. AC-powered models can be powered by the same ac
supply whose current they are monitoring. The 2A and 20A, 85-264Vac, 50/60Hz ("AC1")
models feature additional on-board terminal blocks to supply power to the external load.
All models provide 2000Vdc isolation between the measured ac current and their power
supply, and all are UL/CSA recognized.