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How to read a unit’s nameplate and number · 9 articles
- What the numbers on a bearing mean: type, series, shaft diameterThe first digit of the number gives the bearing type, the next one or two give the series, and the last two give the bore. Bearing 22208 is a spherical roller bearing, series 22, for a 40 mm shaft.
- Letters after a bearing number: K, E, C3, W33 and what they changeThe letters after the digits describe the version: K is a tapered bore for a sleeve, C3 is increased clearance, W33 and E4 are a lubrication groove, ZZ and 2RS are dirt protection. Bearings 22208 and 22208K are the same size but not interchangeable.
- How to read an electric motor nameplate: kW, rpm, IP, insulationTo find a replacement, copy six things from the nameplate: power in kW, voltage with the connection (Δ or Y), speed, frame size, mounting version (B3, B5) and IP rating. Insulation class, duty type and efficiency help choose an equivalent motor, not just a similar one.
- What the letters and numbers in a gearbox model meanA Chinese gearbox model usually encodes the series, the position (horizontal or vertical), whether a motor is attached, the housing size, the ratio and sometimes the motor power. But the order and meaning of the letters differ between plants, so take the exact decoding from the catalog of the plant whose nameplate is on the housing.
- How to read a hydraulic pump model: what YB1-50/50 meansA Chinese hydraulic pump model usually encodes the pump type and its displacement: how many milliliters of oil it delivers per shaft revolution. YB1 is a series of vane pumps, and the numbers after the hyphen are the displacement. But for a new pump to fit, the model alone is not enough: you need the flange, shaft, ports and direction of rotation.
- How to read belt markings: SPB, B, 8M and lengthA belt marking is a profile and a length. SPB, B, SPZ is the section of a V-belt, 8M or 5M is the pitch of a timing belt in millimeters, PJ or PK is a ribbed belt profile. The number is the length, but length can be inside, pitch or outside. A belt is usually the wrong one because nobody noticed which length was printed.
- Drive chain: what 08B and 16A mean and how to get the pitch rightIn the code 08B-2 the first digits are the pitch in sixteenths of an inch (08 is 1/2 inch, 12.7 mm), the letter is the standard series (B European, A American), the digit after the hyphen is the number of strands. 08A and 08B chains with the same pitch are not interchangeable: the rollers and widths differ.
- Pump nameplate: flow, head, speed and how to pick a replacementOn a centrifugal pump nameplate the key figures are flow Q in m³/h and head H in meters at rated speed. That is one point of its curve. A replacement is chosen by that point, the speed and the ports, not by motor power: a pump of the same power can give a different head.
- Oil seals and gaskets: how to write size and material for an orderA shaft seal is written with three numbers: shaft diameter × housing bore diameter × width, for example 45×62×10. Add the type (with or without a dust lip) and the material: NBR for oil up to +100 °C, FKM for heat up to +200 °C. An O-ring is written as inside diameter × cross-section.
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