WEG Medium-Voltage Motors: W50, HGF and M Line

Short answer

WEG, a Brazilian manufacturer, is one of the most installed motor brands in Latin American industry. In medium voltage, the W50 is its totally enclosed fan-cooled (TEFC) squirrel-cage induction motor in a cast-iron frame, from 75 to 1,250 kW and up to 6,600 V per the IEC catalog; the M Line (Master Line) covers large machines, from 220 V to 13,800 V and up to 50,000 kW, open or enclosed; the HGF completes the offer alongside the W22 MV. The W22 is the low-voltage line.

What it is and where it is used

WEG is a Brazilian manufacturer of motors, transformers, drives and automation, with a strong presence in Latin American industry. Its medium-voltage motors include the W50, the HGF and the M Line (Master Line); alongside them is the W22, its low-voltage line, which also has a W22 MV version. They are installed on pumps, compressors, fans, mills, conveyors and extruders in mining, cement, oil and gas, water, paper and food.

A medium-voltage motor is a large asset: its protection, starting and testing are planned together with the rest of the plant. The principle and protection are explained in induction motor and its protection.

Variants: W50, HGF, M Line and W22

Line	Application	Main difference
W50	Medium voltage, general and industrial use	Squirrel cage, totally enclosed fan-cooled (TEFC, IC411), cast iron; 75 to 1,250 kW, up to 6,600 V (IEC catalog)
W50 (NEMA)	North American market	250 to 1,000 hp at 2,300 and 4,160 V
HGF	Medium voltage	Line that WEG lists next to the W22 MV and the W50 in its medium-voltage offer
M Line (Master Line)	Large machines and heavy-duty applications	220 V to 13,800 V, frames 280 to 1800, up to 50,000 kW, open or enclosed
W22 / W22 MV	Low voltage (and a medium-voltage version)	WEG’s high-efficiency line, with NEMA Premium versions

The range data are those WEG publishes in its catalogs; the exact configuration (voltage, poles, cooling, bearings, sensors) is set in the data sheet of each motor.

Main features

Construction: cast-iron frame (W50) or welded plate (M Line in large sizes), with protection degrees for industrial environments.
Stator insulation for medium voltage, with the manufacturer’s impregnation system; this is what insulation and impulse tests monitor.
Sensors: temperature detectors in windings (RTD or PT100) and bearings, and vibration options, which feed protection and monitoring.
Starting: direct, with a soft starter or with a drive; the motor and its insulation must be suitable for the chosen method. See WEG CFW drive.
Associated protection: motor relay with thermal overload, locked rotor, unbalance, ground fault and, on large motors, differential. See motor protection relay and motor differential 87M.

What a W50 includes as standard

The commercial catalog for the IEC market (rev. 04, February 2021) describes the standard W50 configuration in some detail, and it is worth reading before requesting a data sheet:

Class F insulation, service factor 1.00, protection degree IP55 and B3 mounting. The insulation system is VPI (vacuum pressure impregnation) on medium-voltage machines; WISE on low-voltage ones.
Thermal protection: three-wire Pt-100 sensors, two per phase in the winding and one per bearing. Thermistors or thermostats as an option.
Grease-lubricated ball bearings, taconite-type labyrinth seal, and vibration grade A per IEC 60034-14 (grade B optional). Options include sleeve bearings, a roller bearing, an insulated bearing on the non-drive end for use with a drive, and a shaft grounding brush.
Dual-voltage space heaters and an automatic drain plug.
Construction options: IP56, IP65 and IP66 protection degrees, cooling with an independent fan (IC416), an additional terminal box to reach the neutral in star connection, an encoder and tropicalized interior paint.

WEG also publishes special-purpose versions on the same platform. W50 Xec is increased safety (Ex ec, zone 2, temperature class T3). W50 IEEE 841 is severe duty in paper, steel and petrochemical. W50 API 541 is certified up to 60 °C ambient, with a copper rotor, sleeve bearings and a maximum Is/In ratio of 6.5. If your specification mentions IEEE 841 or API 541, it is not a standard W50 under another name: the construction changes.

M Line, HGF and W22: what to look at

M Line. WEG distributes installation, operation and maintenance manuals specific to its horizontal high- and low-voltage squirrel-cage induction motors of the M Line. The document is identified by number and revision. The applicable one is the one that matches the motor and its manufacturing date.
HGF. WEG’s Spanish-language brochure describes the HGF line as totally enclosed fan-cooled cast-iron motors (IC411), with IEC frames 500 to 630 at 2,300 to 6,600 V, class F insulation, IP55 and Pt-100 sensors in the winding and bearings. WEG product sheets for some ratings in IEC 315 to 450 frames state that this presentation was discontinued, with spares and service available for about ten years and the W51 HD line as successor. If you have an HGF installed, confirm the status of your exact model with WEG before planning a replacement.
W22. It is the high-efficiency low-voltage line; do not confuse it with the W50 when ordering spares, because they share a brand but not a platform.

Commissioning and operating points of attention

These are the topics that weigh most on a new or recently repaired medium-voltage motor, in general terms:

Moisture and space heaters. A stored or stopped motor must be kept with its space heaters energized; insulation resistance drops noticeably with moisture and is interpreted with the guide on insulation resistance and polarization index.
Sensor wiring. Three-wire Pt-100 sensors only measure correctly if the relay or temperature monitor is configured for that sensor type; a configuration error shows up as offset readings or false alarms.
Bearings and shaft currents. With a drive, currents circulating through the bearings damage the races; that is why WEG offers the insulated bearing and the grounding brush as options. If the motor was already bought without them, talk to the manufacturer before operating with a drive.
Vibration. Grade A of IEC 60034-14 is the reference value for the motor alone, on its base; the field value depends on the foundation, the coupling and the load.
Starting. The declared Is/In ratio, the load inertia and the grid voltage drop determine the starting time. See starting large motors and voltage drop.

Communications and integration

The motor does not communicate by itself; its protection relay, its drive or starter and the temperature and vibration monitors do. Those signals reach the PLC or DCS over Modbus, EtherNet/IP, PROFINET or another plant protocol, or over IEC 61850 when the motor relay is in the substation. See low-voltage switchboard and MCC and PLC and substation automation.

Frequent technical questions

Where is the manual for the WEG W22 motor? The general manual is in WEG’s download center; the data of the specific motor are on its nameplate and data sheet.
Price and availability of WEG medium-voltage motors: WEG or its distributor handles that. Our work starts with protection, testing and commissioning.
Trip on overload or locked rotor at starting: we review the starting curve, the voltage drop and the relay settings against the motor data. See overcurrent trip on starting or energizing.
Low insulation after a long shutdown: moisture lowers resistance; it is measured before starting and decided with the polarization index.
Motor on a drive: drive pulses put extra stress on the insulation; confirm that the motor is specified for that application.

How we help

At Tiza Group we test and commission medium-voltage motors in industry: insulation resistance and polarization index, winding resistance, impulse tests and functional tests with the relay, in Colombia, or elsewhere on request. See motor testing. Write to us through contact.

References

IEC 60034 (series), rotating electrical machines.
IEEE 43, insulation resistance testing of rotating machinery.
IEEE 522, impulse testing of turn insulation of AC machine windings.
WEG, W50 commercial catalog (IEC market), W50 medium-voltage product sheets, oil and gas motors page (M Line) and stock catalog (W50, W22 MV, HGF).

Frequently asked questions

What power and voltage ratings does the WEG W50 motor cover?

According to the WEG IEC catalog, the W50 ranges from 75 to 1,250 kW, 2 to 12 poles, IEC frames 315 to 450 and voltages from 380 to 6,600 V. WEG later announced new frames starting at IEC 280L, with 185 to 1,500 kW. In the NEMA market it is offered from 250 to 1,000 hp at 2,300 and 4,160 V.

What is the WEG M Line?

It is WEG's line of large motors (Master Line) for heavy-duty applications, for example in oil and gas. WEG gives voltages from 220 V up to 13,800 V, frames 280 to 1800, cast-iron or welded-steel construction, open and enclosed versions and power up to 50,000 kW.

Where do I find the manual for the WEG W22 motor?

WEG publishes general installation, operation and maintenance manuals by line in its download center. The W22 is the low-voltage line; for a medium-voltage motor (W50, HGF or M Line), the useful document is the one for the motor with its serial number, together with its data sheet and drawings.