Model GPS300 MicroMax Interrupter by American Innovations

Flexible, Rugged, Fully-programmable GPS Synchronized Current Interrupter for Cathodic Protection Surveys


American Innovations’ GPS300 is a flexible, rugged, fully-programmable GPS synchronized current interrupter that is designed specifically for cathodic protection (CP) surveys. The GPS300 helps operators meet regulatory 49 CFR, Parts 192 and 195 requirements. It is the smallest interrupter available with a built-in keypad and LCD display and is designed to fit inside most rectifier cabinets. The GPS300 is programmed using the embedded keypad or with a PC via USB. It operates in continuous, daily, dated, and interference modes to fit any interruption schedule. The device can be powered from an AC or DC source for quick installation and reliable operation.

Interference Mode & Influence Studies

Interference Mode synchronously interrupts specific groups of rectifiers to determine the influence of each rectifier on the structure under test. The GPS 300 provides Interference Mode for close interval, depolarization and DCVG surveys with configurable Off, On, and delay settings.

Remote Interruption and Field Data Collection

The GPS300 is fully compatible with Bullhorn® wireless remote monitors with interruption. It also complements the Allegro Field Data Computer to collect, verify, and organize interruption information.

At-a-Glance, the MicroMax GPS300 is …

  • Simple – programmable using a built-in keypad or via USB cable
  • Rugged – able to withstand the most extreme treatment and weather conditions
  • Small - fits easily inside rectifiers
  • Reliable - powered from either an AC or DC source, common in rectifiers
  • Flexible - accommodates any interruption schedule, with continuous, daily, dated and interference modes (Our unique interference mode helps operators determine the influence of each CP source – whether their own or another operator’s – on the structure under test.)
  • Smart - built with AC zero crossing interruption synchronization that switches when AC voltage is at zero volts (This lowers stress on rectifiers and interruption switch components, decreasing the possibility of rectifier and solid state relay failure.)
  • Compatible – works with existing MicroMax interrupters, AI’sRM4010 and RM4150 remote monitors and other GPS-based interrupters
  • Complementary – seamlessly interacts with our Allegro Field Data Computer, Bullhorn Remote Monitoring Systemand Pipeline Compliance System

 Features & Benefits



GPS synchronization 

Keeps all interrupters synchronized for maximum accuracy 

Smallest interrupter with embedded display and keyboard 

  • Takes up less space when transporting 
  • Easily installed inside most rectifiers 

Program interruption schedules with keypad or PC using USB 

Simple to program 

Power directly from rectifier secondary AC tap or DC source 

Quick installation and reliable operation 

Interruption On/Off cycle times up to 999.9 seconds in 0.1 second increments 

Customizable interruption characteristics 

Continuous, daily, dated, and interference modes 

Flexible interruption schedule 




Interference mode with configurable Off, On, and delay cycle settings 

Allows the measurement of Instant Off pipe-to-soil potentials from individual rectifiers during influence and interference studies 

Provides up to 0.5 A at 12 V to control relays 

Can use a wide range of mercury, solid state, standard, or custom relays 

Store up to 9 interruption programs 

Faster setup and common interruption settings using preconfigured schedules 

Works with remote monitors from AI and other vendors 

Compatibility allows system-wide interruption 

Interruption not affected by loss of GPS signal 

Prevents temporary GPS signal loss from affecting survey 

Auto-resume after power loss 

Interruption automatically continues with same program once power is restored 



MicroMax GPS300 Feature 

Specifications Summary 

Input Power

10 - 60 V DC or 8 - 42 V AC 

GPS Synchronization 


Interruption Cycle 

Range: 0.1 - 999.9 s 

Increments: 100 ms 

Relay Drive Capacity 

0.5 A 

Number of Programmable Schedules 

Start Phase 

ON or OFF 


  •  Fully waterproof case 
  • See-through cover 


LCD display 

Operating Temperature

-30 °C to +70 °C 


1 lbs. 11 oz. (0.77 kg) 


6.0” x 4.5” x 2.8" 

Relay Options3 

Mercury Normally Closed (NC): 30 A, 60 A and 100 A 

AC Solid State Normally Closed (NC): 80 A and 100 A 

DC Solid State Normally Closed (NC): 100 A 


Optionally available in ready-to-survey kit with relay, cables, and canvas bag 

Interference Mode

Both the GPS300 and GPS200 provide AI’s unique “Interference Mode.” This interruption cycle enables interference testing with greatly increased productivity and ease of data interpretation. By operating in Interference Mode, it’s possible to determine the influence from multiple CP sources and capture the Instant Off pipe-to-soil potentials, all during a single visit to a test station. In this mode, up to 99 GPS200s, GPS300s and/or Bullhorn remote monitorscan be configured to switch multiple rectifiers so that IR-free pipe-to-soil potentials, as well as the influence from each rectifier under investigation, can be easily collected.

Interference Mode: Influence studies can be very time-consuming and laborious. With MicroMax Interference Mode, as illustrated above, it's now possible to obtain the ON, Instant OFF and influence from each rectifier during a single visit to a test station.