Multi-Amp Test Instrument Brand Unit

Module Feature

Multi-Amp is a well-known American test instrument brand under AVO International. It focuses on power substation commissioning and maintenance test equipment. Its main product portfolio includes secondary relay test sets, high-current primary injection testers, transformer winding resistance testers, CT/PT test instruments and power analyzers such as Penta-Plus. The equipment is widely used for overcurrent relay pickup/timing test, differential relay test, circuit breaker contact resistance test and current transformer excitation curve test. This brand is widely adopted by power utilities and EPC companies.

Working principle

Secondary injection testers output adjustable analog voltage and current signals to simulate fault conditions for protection relays and verify relay action value and operating time. Primary injectors output large AC current directly on the primary side of CT or busbar to check CT ratio, polarity and circuit integrity. Built-in timer records trip response time.

Onboard components

High power AC/DC source module, precision sampling circuit, touchscreen control unit, timer circuit, safety interlock, output terminals and test lead set.

LED indicators

LEDs indicate power ready, high voltage/current output active, interlock status and fault alarm.

Hardware self‑diagnosis

Power-on self-check detects overcurrent, over-temperature, safety interlock open and internal amplifier fault, locks output and shows alarm code.

Programming software

AVO test software, used for test template setup, automatic test sequence running, waveform capture and test report export.

Electrical & Process Parameters

Model:Multi-Amp Brand:Multi-Amp (AVO International) Device type:Power System Test Instrument Function:Protective relay test, primary injection, CT and transformer commissioning test

Mechanical & Structure

Mounting:Portable rugged case Protection class:IP2X Housing:Heavy-duty metal carry enclosure for field service

Environmental

Operating temperature:-20℃ ~ +50℃ Storage temperature:-40℃ ~ +85℃ Ambient humidity:5~95% non‑condensing Certification:IEC 61010, IEC 61850-3 optional Status:AVO original power test instrument brand

Installation

Place the unit on flat stable ground, connect safety earth first before connecting test cables. Set test parameters, confirm test object is de-energized. Follow high voltage and high current safety operation procedure.

Interface

Current/voltage output terminals, measurement input terminals, USB communication port, earth terminal.

Diagnostic

Output no current: Safety interlock not closed, earth missing, internal amplifier fault. Test reading unstable: Poor test clamp contact, electromagnetic interference. Timer not trigger: Auxiliary contact wiring error. Software communication fail: USB cable damage or driver missing.

Product BriefMulti-Amp (AVO International) substation test instruments, primary injection and secondary relay test sets, for power protection commissioning and maintenance.