Danfoss 136N8929 VLT Micro Drive FC 51, 2.2 kW, no RFI filter

A 2.2 kW VLT Micro Drive without RFI filter for filter-free installations

Danfoss order number 136N8929 is the type FC-051P2K2T4E20HXBXCXXXSXXX: a 2.2 kW (3 hp), three-phase 380-480 V VLT Micro Drive FC 51 in frame M2 with a brake chopper and, unlike the more common H3 versions, no integrated RFI filter (type code letters HX). It is a good fit where the installation already has an external filter, where radio interference limits do not apply, or where the supply is an isolated IT network, a case the operating guide for this version addresses. The 2.2 kW H3 version is a different order number (132F0022).

Danfoss publishes a separate operating guide for FC 51 drives without an RFI filter, and that document is attached to this page together with the design guide. Its introduction notes the IT-mains installation case with a maximum supply voltage of 440 V when connected to an isolated network.

Technical specifications

Type code for 136N8929

EMC, selection and availability

Without the internal filter, conducted emission compliance becomes the system builder’s task: use screened motor cable, keep the 15 m limit given for EMC-correct installation, and fit an external filter or a panel-level filter when the first environment category applies. Danfoss lists line filters MCC 107 for the filtered versions; confirm with us which external filter is appropriate for the unfiltered 136N8929. The control card has five digital inputs, two analog inputs, a 0/4-20 mA output, one relay and RS-485, as in the filtered drives.

The store entry carries last-buy and last-delivery notices dated June 30 and September 30, 2026 and recommends the latest version; for a breakdown replacement we confirm what can still be supplied.

Key features of the VLT Micro Drive FC 51

• Very compact chassis: the narrow M2 frame allows side-by-side mounting in small panels and machine cabinets.
• Integrated brake chopper: an external brake resistor can be connected to absorb regenerative energy during fast deceleration or with overhauling loads.
• Coated circuit boards: the coated PCB in this version improves resistance to humidity and airborne contamination.
• Built-in process functions: the FC 51 includes a PI controller, automatic energy optimisation and automatic motor adaptation for simple applications.
• Optional local control panel: this type is supplied without a panel; the plug-in LCP can be added for setup and local operation, and the same panel can be moved between drives.

When a drive without RFI filter is the right choice

An integrated RFI filter contains capacitors connected between the phases and earth. On an IT network, where the supply is isolated from earth or earthed through a high impedance, those capacitors can cause problems with insulation monitoring and, in a fault, can be exposed to excessive voltage. A drive built without the filter avoids this. The same version suits machines that already carry a central filter for several drives, and industrial environments where the applicable EMC category does not demand the integrated filter.

If the installation is a standard earthed TN or TT network in a commercial or light industrial building, the H3 version with integrated filter is usually simpler, because it helps achieve emission limits without additional components. Choosing between the two versions is therefore a question of the supply system and the EMC plan, not of motor power.

Sizing beyond the kilowatt figure

Check the motor full-load current against the continuous output current for the actual supply voltage band, and consider whether the application needs the intermittent overload, for example on a conveyor starting under load. Where a brake resistor is needed, select its resistance and power rating using the design guide, not by guesswork.

Installation and commissioning guidance

Mount the drive vertically on a flat, rigid back plate with free space above and below for cooling. Fit the decoupling plate to provide strain relief and a clean screen connection for the motor and control cables. Keep motor, mains and control cables separated, and connect the screen of the motor cable at both the drive and the motor terminal box.

During commissioning, enter the motor nameplate values, run automatic motor adaptation with the motor cold and uncoupled where possible, then set ramps, speed limits and the control source. Save a copy of the parameters to the LCP so that a replacement drive can be set up quickly.

Applications in Oman and the GCC

Drives of this rating are used on small pumps, ventilation fans, conveyors, mixers, packaging machines and car wash equipment. The filter-free version is relevant on marine and offshore auxiliaries, mobile generator-fed installations and plants with IT supply networks, as well as OEM machines with a common filter.

What to include in an RFQ

• Order number 136N8929 and quantity.
• Supply system type (TN, TT or IT) and voltage.
• Motor nameplate data and the driven load.
• Accessories needed, such as LCP, brake resistor or external filter.
• Delivery location and required timing.

Documents and quotation

Both manufacturer documents are available as downloads on this page. See the Danfoss VLT Micro Drive FC 51 family page for the filtered drives and the AC drives category for the wider range. Send us the label of the drive you are replacing and confirm whether the filter is wanted before ordering.