Australian Made Since 1978 Quality Reliability Local Support
Phone: 0480 312 400 sales@bolec.com.au
Cart
Transport & Mobile Plant

Reliable Electronics.
Keeping You Moving.

Electronic modules and monitoring solutions for commercial vehicles, trucks, buses and specialist mobile equipment.

✓ Overspeed & underspeed monitoring ✓ Automatic alarm or shutdown ✓ 12/24V retrofit-friendly systems
For Fleet, Workshop & OEM Teams

Protect vehicles, operators and uptime with practical electronic control

Monitor speed and engine conditionUse road-speed, RPM and engine-condition inputs to detect abnormal operation.
Control auxiliary functionsTrigger lamps, buzzers, relays, travel locks, door interlocks or shutdown circuits.
Simplify diagnosticsVisible status, programmable thresholds and fault memory support faster workshop diagnosis.
Vehicle Safety, Reliability & Control

Reliable electronic control helps keep commercial vehicles and mobile plant safe, productive and serviceable

Commercial vehicles and mobile equipment operate through vibration, dust, heat, long duty cycles and demanding electrical environments. An unnoticed overspeed, unsafe auxiliary function or engine fault can quickly become downtime or damage. Bolec modules provide practical 12/24V monitoring and control for new builds, fleet upgrades and retrofit installations.

Common Vehicle Control Challenges

Control the conditions that affect safety, reliability and fleet uptime

↻

Road Speed & Engine RPM

Monitor vehicle speed, engine RPM or rotating equipment to trigger warnings, limits and protective actions.

View SS501 →
⚠

Doors, Hydraulics & Interlocks

Prevent unsafe operation of doors, hydraulic functions and auxiliary equipment while a vehicle is moving.

View SS501 →
◉

Engine Protection & Alerts

Monitor oil pressure, temperature, coolant level and alternator status on trucks, buses and heavy equipment.

View EM301 →
⛓

Auxiliary Equipment Control

Use speed- or time-based outputs for beacons, lubrication, PTO systems, alarms and specialist body equipment.

View SS301 →
Practical Vehicle Electronics Architecture

Add focused electronic control without replacing the entire vehicle system

A dedicated speed switch, timer or engine watchdog can add a clearly defined control layer to an existing vehicle or machine. Depending on the application, the module can warn an operator, control an auxiliary circuit, enforce an interlock or initiate a protective shutdown.

DetectRoad speed, RPM, sensor or engine-fault inputs
DecideConfigured thresholds, timing and hysteresis
RespondWarning, lockout, auxiliary control or shutdown

Typical integration points

✓ Truck, bus and mobile-plant electrical systems
✓ OEM controllers and body-builder interfaces
✓ Engine protection and fuel-solenoid circuits
✓ Fleet retrofits and specialist vehicle builds
Featured Vehicle & Mobile Plant Products

Speed control, interlocks and engine protection for mobile equipment

Start with the vehicle signal, operating threshold and required response. Bolec can assist with module selection for fleet retrofit, workshop repair, body building or OEM integration.

Bolec SS501 dual-channel speed switch
SS501
DUAL-CHANNEL SPEED SWITCH
Advanced Vehicle Speed Control

SS501 Dual-Channel Speed & RPM Switch

A microprocessor-controlled frequency switch for monitoring road speed, engine RPM, shafts and rotating machinery. Its two channels support independent setpoints and responses for applications such as zero-speed detection, underspeed shutdown and overspeed alarm.

✓ Dual inputs and relay outputs for multi-stage protection
✓ Road-speed limits, RPM alarms, PTO and auxiliary interlocks
✓ Programmable speed/frequency thresholds
✓ 12/24VDC operation for mobile and fixed plant
View SS501 →
Bolec SS301 speed and rev switch
SS301
MULTI-RANGE SPEED SWITCH
Simple Single-Point Control

SS301 Multi-Range Speed/Rev Switch

A compact universal speed switch for a single adjustable speed or RPM threshold. It accepts common sine or square-wave frequency signals and provides a switched output for alarms, relays or control logic.

✓ Overspeed alarm or speed-dependent control
✓ Adjustable hysteresis helps prevent relay chatter
✓ Inputs from magnetic pickups, ECUs, ignition or sensors
✓ Compact module for retrofits and OEM panels
View SS301 →
Bolec EM301 engine monitor for trucks buses and heavy equipment
EM301
ENGINE MONITOR
Trucks, Buses & Heavy Equipment

EM301 Multi-Input Engine Monitor

A compact electronic watchdog for trucks, buses, agricultural machinery and heavy equipment. It monitors critical engine conditions and can trigger an audible warning or automatic shutdown when a dangerous fault is detected.

✓ Low oil pressure and high temperature protection
✓ Coolant-level and alternator monitoring
✓ Start-up delay and fault memory support diagnosis
✓ 12–24VDC vehicle and mobile-equipment applications
View EM301 →
Vehicle Applications

Where Bolec electronics can improve safety, control and uptime

Trucks & Service Vehicles

Road-speed, RPM, auxiliary control and engine-protection functions for fleet vehicles.

Buses & Passenger Vehicles

Speed-activated door interlocks, warning systems and auxiliary equipment control.

Construction & Earthmoving Plant

Travel locks, hydraulic interlocks, engine monitoring and speed-dependent control.

Emergency & Utility Vehicles

Control beacons, pumps, PTO functions and specialist vehicle body equipment.

Agricultural Machinery

Protect engines and control speed-dependent equipment on 12/24V machines.

OEMs & Body Builders

Compact modules for custom control panels, equipment builds and legacy upgrades.

Product Selection Guide

Match the module to the vehicle signal and required action

ProductBest suited toPrimary functionTypical response
SS501Vehicles and machines requiring two speed/RPM setpoints or channelsDual-channel road-speed, RPM and frequency monitoringAlarm, interlock, staged control or shutdown
SS301Single speed threshold, door lockout or travel-interlock applicationsAdjustable multi-range frequency switchWarning lamp, buzzer, relay or control signal
EM301Truck, bus, agricultural and heavy-equipment engine protectionMulti-input electronic engine watchdogAlarm, fault memory and solenoid shutdown
More Than a Product Number

Application support for new builds, retrofits and reliability upgrades

Tell us what is rotating, where the signal comes from, the normal and fault speeds, supply voltage and what must happen during a fault. We can help narrow down the appropriate Bolec module and discuss practical connection options.

Useful information to provide: equipment type, sensor signal, frequency/RPM range, voltage, desired delay, output load and preferred fail-safe behaviour.

Why Bolec Electronics?

✓ Australian-designed control and protection products
✓ Over four decades of engine and equipment control experience
✓ Solutions for both fixed plant and mobile equipment
✓ Direct technical discussion with a local supplier
Vehicle Electronics Insights

Practical guidance for safer, more reliable mobile equipment

Explore speed-switch selection, frequency monitoring and practical approaches to improving reliability in commercial vehicles and heavy equipment.

Speed switch monitoring mining conveyor equipment
Mining Reliability

How a Speed Switch Can Prevent Costly Downtime in Mining Operations

Read Article →
Comparison of Bolec SS301 and SS501 speed switches
Product Selection

SS301 vs SS501: Which Bolec Speed Switch Should You Choose?

Read Article →
Frequency switches in off-highway heavy equipment
Technical Insight

When Machines Can’t Fail: The Unsung Role of Frequency Switches in Off-Highway Equipment

Read Article →
Frequently Asked Questions

Vehicle speed control, interlocks and engine protection

Can the SS501 monitor both road speed and engine RPM?

Yes. The SS501 supports two channels and can be configured around suitable road-speed, RPM or rotating-shaft frequency signals. The sensor interface, thresholds and output logic must be designed for the specific vehicle application.

What is the main difference between the SS301 and SS501?

The SS301 is suited to a straightforward single adjustable speed threshold. The SS501 provides microprocessor-based dual-channel functionality and is generally the stronger option when two setpoints, two outputs or more flexible speed logic are required.

Can a speed switch control a door lock or hydraulic travel interlock?

Yes. With a suitable vehicle-speed signal, a Bolec speed switch can provide a control output for an external relay, warning device or interlock circuit. The complete circuit and safe-state behaviour must be designed and validated for the vehicle.

Can the EM301 protect engines in trucks and heavy equipment?

Yes. The EM301 is designed for trucks, buses, agricultural machinery and heavy equipment where oil pressure, engine temperature, coolant and alternator conditions must be monitored. Selection depends on the engine sensors, shutdown solenoid and required fail-safe behaviour.

Are these products a complete machine-safety system?

No single module should be treated as a complete safety system by itself. Bolec modules can form part of a wider engineered control and protection solution. Hazard assessment, required performance level, redundancy, wiring, guarding and validation remain the responsibility of the machine or system designer.

Discuss Your Vehicle & Application

Need a speed switch, interlock, timer or engine watchdog?

Send Bolec the equipment type, voltage, sensor signal, operating speed and required alarm or shutdown action. We will help identify the most suitable starting point.

>