WM Hot Stick High Voltage Detector

HASEGAWA WM is a series of propeller-type hot stick high voltage detectors that show the presence of voltage visually by the rotation of a propeller. With 15 versions, from the smallest 6 kV – 22 kV model to the largest 154 kV – 500 kV model, the series covers every level from distribution to transmission. Manufactured in Japan by Hasegawa Electric, the WM series is supplied by HASEGAWA Türkiye, the official HASEGAWA distributor in Türkiye, to customers across Europe.

Each model has an insulating stick made up of several sections; the technical table lists the number of sections, section length, retracted and extended length, stick diameter and weight separately. Teams can therefore choose a model by both the voltage class they work on and the height they need to reach. Distribution network operators, transmission asset operators and power plant maintenance teams use the WM to confirm that a line has remained de-energised after an outage.

Where is it used?

• 10 kV – 20 kV distribution: WM 22 (6 kV – 22 kV) and WM 33 (6 kV – 33 kV); at 340 g and 440 g, the lightest models in the series.
• 33 kV and 66 kV: WM 77A, 77B, 77LB and 77C with an 11 kV – 77 kV range; extended stick lengths between 2.11 m and 3.65 m.
• 110 kV – 150 kV installations: WM 154A, 154B, 154D and 154E (11 kV – 154 kV), or WM 275, 275E and 275F (33 kV – 275 kV), which also cover 220 kV.
• 400 kV transmission: WM 500LF (7.61 m) and WM 500G (8.16 m) with a 154 kV – 500 kV range.

WM or HSR-500?

	WM 500LF / 500G	HSR-500
Operating voltage (AC)	154 kV – 500 kV	250 kV – 550 kV
Use at 220 kV	Suitable	Not suitable
Use at 400 kV	Suitable	Suitable
Weight	2170 g / 2560 g	Approx. 4.5 kg

400 kV is within the range of both products. Because the range of the WM 500LF and 500G starts at 154 kV, they cover both 220 kV and 400 kV with one model; the HSR-500 does not go below 250 kV. For 220 kV, the HST-250 from the HST series is also an option.

Technical specifications

• Operating voltage: 6 kV – 500 kV (varies by model)
• Number of models: 15
• Section length: 0.7 m – 1.3 m; number of sections: 2 – 7
• Stick length: shortest 0.91 m, longest 8.16 m (depending on model)
• Stick diameter: Ø 20 mm – Ø 45 mm
• Weight: 340 g – 2560 g
• Indication: propeller rotation
• Country of origin: Japan

Limits of use and safety

Use each WM model only within its own voltage range; for example, the WM 33's upper limit is 33 kV, so for networks rated above that, choose a WM 77 model. Before testing, extend the stick to a length that provides the required approach distance and check that the sections are firmly joined. As the propeller is a visual indicator, interpret its movement carefully in windy weather and follow the instruction manual for test conditions. Before use, confirm that the instrument responds at a point known to be live. The user must wear gloves and protective equipment rated for the voltage class and hold the stick by the handle area. After a "no voltage" result, earth the line with earthing sets; for general selection criteria, see our voltage detector selection guide.

Why buy from HASEGAWA Türkiye?

• We help you identify the right model among the 15 WM versions for your voltage level and the height you need to reach
• We combine several WM models for teams working at different voltage classes in a single quotation
• We provide a model-by-model technical table and a quotation with a commercial invoice for transmission and distribution projects