DAIHATSU MDP-REVD Speed Switch – Marine Diesel Generator Speed Monitoring Unit
The DAIHATSU MDP-REVD Speed Switch is a marine engine automation and protection component used for monitoring rotational speed on Daihatsu diesel engine and generator installations.
The supplied photograph clearly shows a DAIHATSU MDP-REVD Speed Switch together with multiple boxes of DAIHATSU DIESEL GENUINE PARTS.
The box label visible in the photograph also identifies:
DAIHATSU DIESEL MFG. CO., LTD.
Made in Japan
Speed Switch Assembly
MDP-REVD
Industry spare-parts documentation confirms MDP-REVD applications on Daihatsu auxiliary/generator engines and identifies Meiyo Electric Co., Ltd., Japan as the speed-switch manufacturer in documented installations.
Product Information
Brand: DAIHATSU
Equipment: Marine Diesel Engine / Generator Engine
Component: Electronic Speed Switch
Model: MDP-REVD
Associated Manufacturer: Meiyo Electric Co., Ltd., Japan
Power Supply: 24 VDC on documented versions
Signal: Pulse-based engine speed measurement
Application: RPM monitoring, alarm/control and engine protection
Different MDP-REVD configurations exist, so the exact nameplate and initial settings should always be checked before replacement. Documented units include both 2.5 W and 3.2 W versions.
What Does the MDP-REVD Speed Switch Do?
The MDP-REVD receives a pulse signal corresponding to engine rotational speed and uses it to monitor engine RPM.
Depending on the configured installation, its outputs can be used for functions such as:
• Engine speed monitoring
• Low-speed indication
• Rated-speed detection
• Overspeed-related control/protection
• Alarm generation
• Generator control logic
• Engine shutdown/interlock logic
• RPM signal transmission
Some documented MDP-REVD versions provide a 4–20 mA analog output together with multiple relay/contact outputs.
Typical Technical Configuration
Published examples of the MDP-REVD show specifications such as:
Power Supply: 24 VDC
Analog Output: 4–20 mA on applicable versions
Pulse Input: Engine-speed pulse signal
Contact Outputs: Multiple programmable/set speed contacts
Hysteresis: Configurable according to installation
Speed Display: Digital RPM indication
One documented Daihatsu/Meiyo unit uses individual #12, #13, #14 and #14L speed thresholds, demonstrating that the switch can be configured for several engine-control events.
Because initial settings vary by engine and vessel, replacement units should not be installed solely on the basis of the MDP-REVD model number.
DAIHATSU Generator Engine Application
The MDP-REVD is documented as a speed switch used in Daihatsu auxiliary/generator engine systems.
For example, a Daihatsu 5DK-20 generator diesel engine spare-parts reference identifies an MDP-REVD speed switch installed in the main switchboard, together with a separate pulse-type speed sensor on the auxiliary generator engine.
This illustrates the typical signal path:
Engine Rotation → Pulse Sensor → MDP-REVD Speed Switch → Alarm / Control / Protection System
Main Functions
• Engine RPM measurement
• Generator speed monitoring
• Pulse-signal processing
• Speed threshold detection
• Multiple relay/contact outputs
• 4–20 mA output on applicable versions
• Low / rated / high-speed control functions
• Alarm-system interface
• Generator control interface
• Engine safety and protection-system integration
Common Problems & Troubleshooting
No RPM Indication
Check:
• 24 VDC power supply
• Pulse sensor
• Sensor wiring
• Terminal connections
• Pulse configuration
• Internal electronics
RPM Reading Is Incorrect
Verify:
• Pulse-per-revolution setting
• Reduction gear ratio
• Full-scale setting
• Sensor air gap/installation
• Pulse signal quality
Speed Contact Does Not Operate
Check the programmed/set RPM, hysteresis, contact-output configuration and associated relay wiring.
4–20 mA Output Incorrect
For versions equipped with analog output, check the signal loop, ZERO/SPAN adjustment, supply and receiving equipment.
Engine Alarm Appears at Wrong RPM
The replacement unit may have different initial settings from the original unit. Compare the complete nameplate/settings before commissioning.
Important Replacement Information
When ordering an MDP-REVD, provide a photograph of the complete label whenever possible.
Important information includes:
Model: MDP-REVD
Supply Voltage
Power Consumption
Initial Setting
Hysteresis
#12 / #13 / #14 / #14L Settings
Contact Output Mode
Full Scale
Reduction Gear Ratio
Pulse Setting
Analog Output Specification
This is important because multiple MDP-REVD configurations are documented in the marine market.
DAIHATSU Speed Switch & Engine Automation Spare Parts
SM MARINE SERVICE™ can support sourcing of:
• DAIHATSU MDP-REVD Speed Switch
• Meiyo Electric MDP-REVD
• Engine Speed Sensors
• Pulse Sensors
• RPM Sensors
• Engine Alarm Units
• Generator Control Components
• Engine Safety Modules
• Pressure Switches
• Temperature Sensors
• Engine Control PCBs
• Governor Components
• Solenoid Valves
• Engine Monitoring Components
• DAIHATSU Genuine Parts
• Complete Marine Engine Automation Spare Parts
Available condition may include:
Brand New Genuine • New OEM • Used • Tested Working • Refurbished • Reconditioned
Marine Applications
DAIHATSU diesel generator engines and their automation components are widely used aboard:
• Bulk Carriers
• Container Ships
• Oil Tankers
• Chemical Tankers
• LNG / LPG Carriers
• General Cargo Ships
• Offshore Vessels
• Passenger Ships
• Merchant Vessels
The MDP-REVD is especially relevant when maintaining existing Daihatsu auxiliary-engine and generator control systems.
Why Keep the Existing MDP-REVD System?
A vessel may already have its:
• Pulse sensor
• Main switchboard wiring
• Alarm system
• Generator control circuit
• Shutdown logic
• RPM indication
• Engine safety system
configured around the MDP-REVD.
Replacing the failed speed switch with the correct matching unit can therefore be considerably easier than modifying the complete engine-control system.
Frequently Asked Questions – FAQ
What is DAIHATSU MDP-REVD?
It is an electronic speed switch used to monitor rotational speed in marine diesel engine and generator applications.
Who manufactures the MDP-REVD?
Marine spare-parts references identify Meiyo Electric Co., Ltd., Japan as the manufacturer of MDP-REVD units used with Daihatsu equipment.
What power supply does MDP-REVD use?
Documented versions operate on 24 VDC.
Does MDP-REVD have 4–20 mA output?
Some documented versions provide a 4–20 mA analog output.
Can all MDP-REVD units be directly interchanged?
Not necessarily. Initial speed settings, hysteresis, pulse configuration, output mode and other parameters can differ. The old unit's complete specification should be checked before replacement.
Is MDP-REVD used with Daihatsu generator engines?
Yes. It is documented as a speed switch for Daihatsu auxiliary/generator engine applications, including a documented 5DK-20 installation.
Where can I buy DAIHATSU MDP-REVD?
SM MARINE SERVICE™ can support worldwide supply of DAIHATSU MDP-REVD speed switches and associated marine engine automation spare parts, subject to stock availability.
Short Product Description
DAIHATSU MDP-REVD Speed Switch is a marine diesel engine and generator RPM monitoring component associated with Meiyo Electric Co., Ltd., Japan. Documented versions operate from 24 VDC and can provide multiple speed contact outputs and, on applicable versions, a 4–20 mA analog RPM signal. SM MARINE SERVICE™ supplies DAIHATSU speed switches, pulse sensors, engine automation components and genuine marine diesel spare parts worldwide.
SM MARINE SERVICE™
Marine Automation • Engine Control • Navigation • Marine Spare Parts
Available Supply:
Brand New Genuine • OEM • Used • Tested • Refurbished • Reconditioned
Support:
Worldwide Shipping • Marine Equipment Sourcing • Technical Support • Hard-to-Find & Obsolete Spare Parts
Contact Information
SM MARINE SERVICE™
Samir Market, D.T. Road, Pahartali, Chattogram, Bangladesh
Mobile / WhatsApp: +88 01818 929292
Email: info@smmarineservice.com
Website: www.smmarineservice.com
