A motor nameplate carries a dozen abbreviations: IM B35, IP55, IC 411, Cl. F, S1, IE3. Each stands for a separate parameter, and a mistake in any of them gives you a motor that will not fit the base, overheats or fails the site conditions. Below: what each code means, where to find it on the nameplate and how to describe the motor so that a European equivalent can be selected without follow-up questions.
What is on the nameplate
Take a typical induction motor and read one nameplate line piece by piece:
| Field | Example | What it means |
|---|---|---|
| Frame | 132M | Shaft centre height 132 mm; M is the medium frame length (S short, L long). The length sets the distance between the foot holes. |
| Poles / speed | 4 · 1455 min⁻¹ | Four poles means 1500 min⁻¹ synchronous speed at 50 Hz; rated speed is lower by the slip. |
| Power | 7.5 kW | Rated shaft output, not the power drawn from the supply. |
| Voltage and connection | 400 V Δ / 690 V Y | Windings in delta for 400 V or in star for 690 V. State the voltage of your own network. |
| Mounting | IM B35 | Feet and flange, horizontal shaft (see the mounting section). |
| Protection | IP55 | Dust and water jets (see the IP section). |
| Cooling | IC 411 | Totally enclosed motor with a shaft-mounted fan. |
| Insulation | Cl. F | Winding thermal class 155 °C. |
| Duty | S1 | Continuous operation at constant load. |
| Efficiency class | IE3 | High efficiency class per IEC 60034-30-1. |
Mounting: the IM code (IEC 60034-7)
The IM code answers two questions: are there feet and a flange, and is the shaft horizontal (letter B) or vertical (V). It is written in two ways: alphanumeric (IM B3) and four-digit numeric (IM 1001). Both appear on nameplates, so the table shows them side by side.
| Code | Numeric code | What it is |
|---|---|---|
| IM B3 | 1001 | foot-mounted, horizontal shaft, feet down |
| IM B5 | 3001 | no feet, large flange FF with through holes |
| IM B35 | 2001 | feet and large flange FF |
| IM B14 | 3601 | no feet, small flange FT with tapped holes |
| IM B34 | 2101 | feet and small flange FT |
| IM V1 | 3011 | large flange, shaft down |
| IM V3 | 3031 | large flange, shaft up |
| IM V5 | 1011 | feet, wall-mounted, shaft down |
| IM V6 | 1031 | feet, wall-mounted, shaft up |
| IM V18 | 3611 | small flange, shaft down |
| IM V19 | 3631 | small flange, shaft up |
Motors from CIS countries often carry GOST 2479 codes: IM1081, IM2081, IM3081, IM3681. They map to IM B3, B35, B5 and B14 respectively.
Frame size, shaft and flanges
Frame size is the shaft centre height above the mounting plane in millimetres (132 mm for a 132M motor). Together with the length letter (S, M, L) it fixes the distance between the foot holes, and IEC 60072 also fixes the shaft diameter and length and the flange size. That is why a European motor of the same frame and length fits the same feet as an AIR-series motor of that frame.
| Frame H, mm | Shaft D, mm | Flange FF (B5) | Flange FT (B14) |
|---|---|---|---|
| 71 | 14 | FF130 | FT85 |
| 80 | 19 | FF165 | FT100 |
| 90 | 24 | FF165 | FT115 |
| 100 / 112 | 28 | FF215 | FT130 |
| 132 | 38 | FF265 | FT165 |
| 160 | 42 | FF300 | — |
| 180 | 48 | FF300 | — |
These are typical values for common designs; check exact dimensions against the catalogue sheet. For foot-mounted motors H, the hole spacings A and B, shaft diameter D and length E must match; for flange motors, the spigot diameter, the bolt circle and the shaft diameter.
Ingress protection IP and impact rating IK
Two digits follow the letters IP. The first (0–6) is protection against solid objects and dust, the second (0–9) against water. The ones you meet most often on motors:
| Code | Solids | Water |
|---|---|---|
| IP23 | objects over 12 mm | drops at up to 60° (open motor) |
| IP54 | dust partly | splashing from any direction |
| IP55 | dust partly | water jets |
| IP56 | dust partly | powerful jets |
| IP65 | dust-tight | water jets |
| IP66 | dust-tight | powerful jets |
IP55 is the standard for modern motors. For pressure washing or a dusty workshop choose IP65–IP66. The IK impact rating (IEC 62262) is rarely marked on motors. Standard conditions under IEC 60034-1: ambient up to 40 °C, altitude up to 1000 m. In heat or at altitude the motor is derated, so state the real conditions in the enquiry.
Cooling: the IC code
The IEC 60034-6 code describes how the heat is removed. The most common ones:
| Code | Cooling method |
|---|---|
| IC 01 | open motor, self-ventilated |
| IC 06 | open motor, separate fan with its own drive |
| IC 410 | enclosed, no fan, the frame sheds the heat |
| IC 411 | enclosed, shaft-mounted fan (the most common) |
| IC 416 | enclosed, separate fan with its own drive |
| IC 81W | enclosed, water jacket |
Insulation, duty and efficiency class
The insulation class shows what temperature the winding withstands, not what it reaches in service.
| Class | Maximum temperature | Permitted rise at 40 °C |
|---|---|---|
| B | 130 °C | 80 K |
| F | 155 °C | 105 K |
| H | 180 °C | 125 K |
A common European combination is class F insulation with a class B temperature rise, which leaves a margin in temperature and service life.
Duty S1–S10 under IEC 60034-1 describes how the load varies over time. A wrong duty is one of the most frequent causes of overheating.
| Duty | Load pattern |
|---|---|
| S1 | continuous, constant load |
| S2 | short-time (10, 30, 60, 90 min), then the motor cools down |
| S3 | intermittent, starting does not affect heating; the cyclic duration factor is specified |
| S4–S5 | intermittent with frequent starts; S5 adds electric braking |
| S6–S8 | continuous with periodic load, starting and braking |
| S9–S10 | non-periodic or discrete loads |
The efficiency class IE1–IE4 (IEC 60034-30-1) is the motor efficiency. IE3 or better is required for new motors in the EU, so a European equivalent usually has higher efficiency than an old motor with a CIS data sheet.
DC motors
In a DC motor the excitation circuit matters as well: it decides how the motor behaves under load and how its speed is controlled.
| Excitation | Terminals | Characteristics |
|---|---|---|
| Separate | A1–A2, F1–F2 | the field is supplied separately; stable speed, controlled by armature voltage or field current |
| Shunt | A1–A2, E1–E2 | field in parallel with the armature; stiff characteristic, simple machine-tool and fan drives |
| Series | A1–A2, D1–D2 | field in series with the armature; high starting torque (traction, hoists), races without load so it must never run unloaded |
| Compound | A, D, E | combination of shunt and series windings; a compromise between torque and speed stability |
Terminal marking per IEC 60034-8: A — armature, B — commutating poles, C — compensating winding, D — series field, E — shunt field, F — separate field. DC motors usually have forced ventilation (IC 06 or IC 416), and the speed sensor (tacho-generator, encoder) is a separate item.
CIS designations and the European equivalent
The abbreviations in old data sheets have direct IEC counterparts.
| On the data sheet | Meaning | IEC term |
|---|---|---|
| АИР100L4, 4А, 5А | induction series with IEC frame sizes | frame 100L, 4 poles, the same mounting dimensions |
| IM1081, IM2081, IM3081 | arrangement per GOST 2479 | IM B3, B35, B5 |
| У2, У3, УХЛ4 | climatic version | conditions per IEC 60034-1: temperature and altitude; protection is given by the IP code |
| ПВ 40 % | cyclic duration factor | duty S3 with a 40 % load factor in the cycle |
| 380 V | supply voltage | 400 V ±10 % is the European motor voltage; check the nameplate |
| 2П, 4П, ПБС | DC motors | IEC DC motors with the same shaft height and excitation scheme |
What to state in a motor enquiry
So that the supplier can select an equivalent without follow-up questions, collect these from the nameplate or data sheet:
- Power in kW and the number of poles or rated speed.
- Voltage, frequency, winding connection.
- Frame with the length letter (for example 132M) or the old series designation.
- Mounting: IM B3, B5, B35, V1 and so on, and the shaft position.
- Shaft: diameter and length, keyway; flange, if there is one.
- IP rating, IC cooling method, altitude and ambient temperature.
- Duty S and the supply: mains or frequency converter.
- Extras: thermal protection (PTC, PT100), heater, encoder, brake, explosion protection (a separate subject).
- A photo of the nameplate: most parameters can be recovered from it.
Where to select
Motors from stock and to order are in the catalogue (section “Electric motors”); low-voltage motors and drives are on ukrsk.com.ua (Ukrainian page). On selecting replacements for other equipment see How to read ТМГ, ТСЗ, ТДН designations and the guide to supplying equipment from the EU.
Codes and classes are given per the IEC 60034 series and IEC 60072. Exact values for a given motor are set by its catalogue sheet.
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