Why Choose the Finder 99.01.3.000.00 Diode EMC Suppression Module?
The Finder 99.01.3.000.00 is a standard-polarity diode suppression module from the Finder 99 Series, designed to protect compatible DC relay coil circuits against reverse-voltage transients. Operating across a 6–220 V DC range, this plug-in accessory provides a practical method of suppressing the voltage spikes generated when an electromagnetic relay coil is switched off.
Designed for compatible Finder relay sockets, the module uses a recovery diode to provide a discharge path for the energy stored in the relay coil. This helps limit potentially damaging voltage peaks and reduces electrical disturbances in associated control circuitry.
The Finder 99.01.3.000.00 features standard DC polarity, with the positive supply connected to terminal A1. It is a diode-only protection module without an integrated LED indicator. Because diode suppression can increase relay release time by approximately a factor of three, it is particularly suitable for applications where effective coil transient suppression is more important than rapid relay release.
Key Advantages
- Effective coil protection: Helps suppress reverse-voltage peaks generated when DC relay coils are de-energised.
- Wide DC voltage range: Suitable for compatible relay coil circuits operating between 6 V and 220 V DC.
- Standard-polarity design: Provides a defined connection arrangement with positive voltage applied to terminal A1.
- Recovery diode suppression: Provides a discharge path for stored inductive energy.
- Plug-in installation: Designed for installation in compatible Finder relay sockets.
- Reduced switching transients: Helps limit voltage disturbances affecting associated electrical control equipment.
- Compact accessory: Integrates the suppression function into a relay socket assembly.
- DC-specific protection: Designed specifically for direct-current relay coil applications.
- Maintenance convenience: Allows the suppression module to be replaced independently of the relay in suitable socket assemblies.
- Finder 99 Series integration: Forms part of Finder's range of relay coil indication and EMC suppression accessories.
Key Features
- Finder 99 Series relay protection accessory.
- Model: 99.01.3.000.00.
- Diode-only EMC suppression module.
- 6–220 V DC operating voltage range.
- Standard DC polarity.
- Positive supply connection to relay coil terminal A1.
- Integrated recovery diode for inductive coil transient suppression.
- Designed for compatible Finder relay sockets.
- Helps limit reverse-voltage peaks when the relay coil is switched off.
- Can increase relay release time by approximately a factor of three.
- No integrated LED indication.
- Not intended for AC relay coil supplies.
- Suitable for industrial automation and electrical control systems.
- Plug-in accessory construction.
Technical Specifications
- Manufacturer: Finder
- Series: 99 Series
- Product code: 99.01.3.000.00
- Product family: 99.01
- Product type: Relay coil protection module
- Module function: EMC suppression
- Suppression component: Recovery diode
- Polarity: Standard polarity
- Operating voltage range: 6–220 V DC
- Minimum operating voltage: 6 V DC
- Maximum operating voltage: 220 V DC
- Supported supply type: DC only
- Positive supply connection: Terminal A1
- LED indication: Not included
- Protection principle: Suppression of relay coil reverse-voltage transients
- Effect on relay release time: Approximately three times the unsuppressed release time
- Mounting method: Plug-in installation in compatible Finder relay sockets
- Compatible socket examples: Finder 90.20, 90.21, 94.72, 94.73, 94.74, 94.82, 95.63, 95.65, 96.72 and 96.74
- Accessory category: Relay Coil Suppression Modules
How the Finder 99.01.3.000.00 Diode Suppression Module Works
When a DC electromagnetic relay coil is energised, energy is stored in its magnetic field. When the coil supply is interrupted, this stored energy can generate a high reverse-voltage transient. Without suitable suppression, the transient may place additional electrical stress on the device switching the relay coil and contribute to electromagnetic interference.
The Finder 99.01.3.000.00 uses a recovery diode connected across the relay coil circuit. During normal energisation, the diode is reverse-biased. When the coil supply is removed, the diode provides a path for the coil current to circulate and decay, limiting the reverse-voltage peak.
This suppression method is particularly effective for DC coils, but it also affects the relay's switching dynamics. Finder identifies an approximate threefold increase in relay release time when using this type of diode module. Where fast contact release is important, a suitable varistor or RC suppression module may be preferable.
Correct polarity is essential. The positive DC supply must be connected to terminal A1 of the associated relay coil. Reversing the supply can forward-bias the suppression diode and create an unintended current path.
The module does not contain an LED indicator and does not perform the relay's switching function. It is intended solely for suppression of compatible DC relay coil transients and must be used with an appropriate Finder relay and socket combination.
Typical Applications
- DC relay coil protection in industrial automation panels.
- PLC output circuits controlling compatible DC relays.
- Industrial machinery control systems.
- Electrical control cabinets using Finder relay sockets.
- Auxiliary relay circuits in switchgear assemblies.
- Industrial process automation.
- DC-operated signalling and interlocking systems.
- Motor control auxiliary relay circuits.
- Building automation and HVAC control equipment.
- OEM machinery and equipment manufacturing.
- Electrical installations requiring relay coil transient suppression.
- Maintenance and replacement of relay suppression accessories.
- Control panel refurbishment and upgrades.
- DC control systems where increased relay release time is acceptable.
