NEMA及IEC標(biāo)準(zhǔn)下的電機(jī)銘牌識(shí)別（連載二）

國際電工委員會(huì) (IEC) 是與北美國家電氣制造商協(xié)會(huì) (NEMA) 標(biāo)準(zhǔn)的國際對(duì)應(yīng)機(jī)構(gòu)。

NEMA 和 IEC 標(biāo)準(zhǔn)使用不同的術(shù)語，但它們?cè)陬~定值方面基本相似，并且在大多數(shù)常見應(yīng)用中可以互換。簡而言之，NEMA 標(biāo)準(zhǔn)往往更為保守，而 IEC 標(biāo)準(zhǔn)則更為精確、具體且分類更清晰。

現(xiàn)在了解了 NEMA 電機(jī)術(shù)語，下面將介紹 IEC 最常見的名稱及其與 NEMA 標(biāo)準(zhǔn)的關(guān)系。

The International Electrotechnical Commission (IEC) is the international counterpart to the North American- National Electrical Manufacturers Association (NEMA) standards.

The NEMA and IEC standards use different terms, but they are essentially analogous in ratings and, for most common applications, are largely interchangeable. In brief NEMA standards tend to be more conservative while IEC standards tend to be more precise, specific and more categorized.

Now that we understand the NEMA motor terminology, here’s a primer on the most common designations of IEC and how they relate to NEMA standards.

框架關(guān)系

Frame relationships

IEC 和 NEMA 電機(jī)都使用字母代碼來指定物理框架尺寸，但代碼不同。

IEC 電機(jī)的機(jī)座號(hào)由兩部分字母/數(shù)字代碼組成。代碼的字母部分指定物理框架尺寸，而數(shù)字部分指定通用框架尺寸。

字母部分可能比較復(fù)雜，例如，IEC 電機(jī)的“K”代碼相當(dāng)于 NEMA 電機(jī)的“H”，而 IEC 電機(jī)的“H”代碼相當(dāng)于 NEMA 電機(jī)的“D”。

代碼的數(shù)字部分（表示機(jī)座尺寸）比較容易混淆，重疊部分也較少；例如，IEC 的“56”適用于亞分功率電機(jī)，而 NEMA 的“56”適用于 ? - 1.5 HP 電機(jī)。

IEC 還通過代碼定義電機(jī)的安裝位置和連接法蘭類型。一些較常見的安裝位置代碼包括 B3（代表底腳安裝）和 B5（代表無底腳安裝）。IEC 定義了三種不同的法蘭類型：FF、FT 和 FI 法蘭。FF 法蘭帶有通孔螺栓孔，適用于 56 至 280 的機(jī)架尺寸。FT 法蘭帶有螺紋螺栓孔，也適用于 56 至 280 的框架尺寸。

請(qǐng)注意，所有 IEC 尺寸均為公制單位。

Both IEC and NEMA motors use a letter code to specify the physical frame dimensions, but the codes are different.

The frame designation for IEC motors is composed of a two-part letter/number code. The letter portion of the code specifies the physical frame dimensions, while the number portion of the code specifies the general frame size.

The letters can get especially tricky, for example, a "K" code for an IEC motor is equivalent to a NEMA "H", whereas an IEC "H" is equivalent to a NEMA "D".

The numeric portion of the code (indicating frame size) is less confusing and there is less overlap; for instance an IEC "56" is for sub-fractional motors whereas a NEMA "56 is from ? - 1.5 HP motors).

The IEC also defines a motor's mounting position and connecting flange type by a code. A couple of the more common mounting position codes include B3 for foot mounted and B5 for footless. Three different flange types are defined: FF, FT and FI flanges. The FF flange has through bolt holes, and is available for frame sizes from 56 to 280. The FT flange has threaded bolt holes and is also available for frame sizes from 56 to 280.

Note that all the IEC dimensions are in metric units.

外殼標(biāo)識(shí)

Enclosure designations

與 NEMA 類似，IEC 也使用標(biāo)識(shí)來指示電機(jī)外殼提供的防護(hù)等級(jí)。然而，當(dāng) NEMA 標(biāo)識(shí)以文字形式出現(xiàn)時(shí)，例如“開放式防滴漏”或“全封閉式風(fēng)扇冷卻”，IEC 則使用兩位數(shù)的“防護(hù)等級(jí)”代碼來描述外殼保護(hù)電機(jī)免受環(huán)境影響的程度。第一位數(shù)字表示電機(jī)防止固體物體進(jìn)入的防護(hù)等級(jí)，第二位數(shù)字表示防止水進(jìn)入的防護(hù)等級(jí)。兩位數(shù)字前面帶有字母“IP”。

第一位數(shù)字的含義如下：

0 - 無防護(hù)

1 - 可防止直徑大于 50 毫米（約 2 英寸）的物體進(jìn)入，例如手

2 - 可防止直徑大于 12 毫米（約 1/2 英寸）的物體進(jìn)入，例如手指

4 - 可防止直徑大于 1 毫米（約 0.04 英寸）的物體進(jìn)入，例如小型工具和電線

5 - 全面防護(hù)，包括防塵。

第二位數(shù)字表示防水等級(jí)。具體等級(jí)如下：

0 - 無防護(hù)

1 - 可防止垂直落水

2 - 可防止與垂直方向成 15 度角的落水

3 - 可防止與垂直方向成 60 度角的噴水

4 - 可防止來自任何方向的濺水

5 - 可防止來自各個(gè)方向的噴射水流

6 - 可防止波濤洶涌的海水

7 - 可防止浸入深度在 0.15 至 1.0 米之間的水深

8 - 可防止長時(shí)間浸入深水

總體而言，NEMA 的標(biāo)識(shí)更具描述性和通用性，而 IEC 的 IP 代碼則更精確，定義更狹窄。對(duì)于大多數(shù)工業(yè)應(yīng)用，IP 22 指的是開放式防滴電機(jī)，IP44 或 IP54 指的是全封閉式電機(jī)，IP45 指的是防風(fēng)雨電機(jī)，IP55 指的是可沖洗電機(jī)。對(duì)于防爆電機(jī)，國家電氣規(guī)范定義的危險(xiǎn)環(huán)境與 IEC“防火”電機(jī)的危險(xiǎn)環(huán)境相同。

Like NEMA, IEC has designations indicating the protection provided by a motor's enclosure. However, where NEMA designations are in words, such as Open Drip Proof or Totally Enclosed Fan Cooled, the IEC uses a two-digit "Index of Protection" code to describe how well the enclosure protects the motor from the environment. The first digit indicates how well protected the motor is against the entry of solid objects, the second digit refers to water entry. The two digit number is preceded by the letters “IP”.

Here's what the first digit means:

0 - No protection

1 - Protection against objects larger than 50mm (about 2 in.) in diameter, like hands

2 - Protection against objects larger than 12mm (about 1/2 in.) in diameter, like fingers

4 - Protection against objects larger than 1mm (about 0.04 in.) in diameter, like small tools and wires

5 - Complete protection, including dust-tightness.

The second digit signifies protection against water entry. Here are those ratings:

0 - No protection

1 - Protected from water falling straight down

2 - Protected from water falling as much as 15 deg from vertical

3 - Protected from spraying water as much as 60 deg from the vertical

4 - Protected from splashing water coming from any direction

5 - Protected against jets of water from all directions

6 - Protected from heavy seas

7 - Protected against the effects of immersion to depths of between 0.15 and 1.0 m

8 - Protected against the effects of prolonged immersion at depth

By way of general comparison, the NEMA designations are more descriptive and general, whereas the IEC IP codes are more precise and narrowly defined. For most industrial application, an IP 22 relates to open drip-proof motors, IP44 or IP54 to totally enclosed, IP45 to weatherproof, and IP55 to wash-down duty motors. For explosion proof motors, the hazardous atmospheres defined by national electrical code parallel those of the IEC "flame-proof" motors.

冷卻標(biāo)識(shí)

Cooling designations

同樣，IEC 使用字母和數(shù)字組成的 IC 代碼來表示電機(jī)的冷卻方式。幾乎每種冷卻方式都有單獨(dú)的代碼，從小型風(fēng)冷電機(jī)到大型液冷電機(jī)。代碼可能非常復(fù)雜，最多包含四個(gè)字母和四位數(shù)字。

以下列出了一些較常見的“短代碼”：

IC 01 - 第一位數(shù)字表示空氣可以自由進(jìn)出電機(jī)。第二位數(shù)字表示氣流由內(nèi)置風(fēng)扇或“自感應(yīng)”產(chǎn)生。由于內(nèi)部風(fēng)扇的作用，這對(duì)應(yīng)于標(biāo)準(zhǔn)的 NEMA 開放式風(fēng)冷電機(jī)。

IC 40 - 第一位數(shù)字表示框架表面（外殼）已冷卻（即無內(nèi)部氣流）。第二位數(shù)字表示僅通過對(duì)流冷卻，無風(fēng)扇作用。這對(duì)應(yīng)于 NEMA 全封閉、無通風(fēng) (TENV) 電機(jī)。

IC 41 - 第一位數(shù)字同樣表示框架表面冷卻，但第二位數(shù)字表示電機(jī)氣流由內(nèi)置風(fēng)扇引起。這對(duì)應(yīng)于 NEMA 全封閉風(fēng)冷 (TEFC) 電機(jī)。

IC 48 - 第一位數(shù)字表示外部框架/外殼表面已冷卻（即無內(nèi)部氣流）。但第二位數(shù)字表示電機(jī)處于驅(qū)動(dòng)風(fēng)扇或鼓風(fēng)機(jī)的氣流中。這對(duì)應(yīng)于 NEMA 全封閉風(fēng)冷電機(jī) (TEAO)。這適用于電機(jī)處于其驅(qū)動(dòng)的風(fēng)扇或鼓風(fēng)機(jī)的氣流中，從而通過風(fēng)扇作用進(jìn)行冷卻的用途。

因此，在大多數(shù)實(shí)際應(yīng)用中，IC 01 代表 NEMA 開放式設(shè)計(jì)，IC 40 代表全封閉無通風(fēng) (TENV)，IC 41 代表全封閉風(fēng)冷 (TEFC)，IC 48 代表全封閉風(fēng)冷 (TEAO)。

Again, IEC uses a letter and number IC code to designate how a motor is cooled. There is an individual code for just about every type of cooling method, from small fan cooled motors to large liquid cooled motors. The code can get quite complex; up to a four-letter and four-digit code.

A few of the more common “short codes" are shown below:

IC 01- The first digit indicates that the air can flow freely in and out of the motor. The second digit indicates that the airflow is caused by an integral fan, or "self-induced". This corresponds to a standard NEMA open fan-cooled motor because of the internal-fan action.

IC 40 - The first digit means the frame surface (external enclosure) is cooled (i.e. no internal flow). The second digit indicates that cooling by convection only without a fan action. This corresponds to a NEMA totally enclosed, non-vented (TENV) motor.

IC 41 - The first digit again indicates frame-surface cooling, but the second indicates that airflow over the motor is caused by an integral fan. This corresponds to a NEMA Totally-Enclosed FanCooled (TEFC) motor.

IC 48 - The first digit indicates that the external frame/enclosure surface is cooled (i.e., no internal flow). But the second says that the motor is in the air stream of the driven fan or blower. This corresponds to a NEMA Totally Enclosed, Air-Over motor (TEAO). This relates to uses where the motor is in the air stream of the fan or blower it drives, and is thus cooled by fan action.

Thus for most practical purposes, IC 01 relates to a NEMA open design, IC 40 Totally Enclosed Non-Ventilated (TENV), IC 41 to Totally Enclosed Fan Cooled (TEFC), and IC 48 to Totally Enclosed Air Over (TEAO).

占空比

Duty Cycles

NEMA 電機(jī)以兩個(gè)或三個(gè)術(shù)語之一來表示占空比：連續(xù)、間歇或特殊負(fù)載（通常以分鐘表示）。IEC 將其分為八個(gè)等級(jí)：

S1 - 連續(xù)工作模式：電機(jī)以恒定負(fù)載運(yùn)行足夠長的時(shí)間以達(dá)到溫度平衡。

S2 - 短時(shí)工作模式：電機(jī)以恒定負(fù)載運(yùn)行，但運(yùn)行時(shí)間不足以達(dá)到溫度平衡，而停機(jī)時(shí)間足夠長，使電機(jī)達(dá)到環(huán)境溫度。

S3 - 間歇周期工作模式：在恒定負(fù)載下，以順序、相同的運(yùn)行和停機(jī)周期運(yùn)行。永遠(yuǎn)不會(huì)達(dá)到溫度平衡。啟動(dòng)電流對(duì)溫升影響很小。

S4 - 帶啟動(dòng)的間歇周期工作模式：在恒定負(fù)載下，以順序、相同的啟動(dòng)、運(yùn)行和停機(jī)周期運(yùn)行。不會(huì)達(dá)到溫度平衡，但啟動(dòng)電流會(huì)影響溫升。

S5 - 間歇式周期運(yùn)行，帶電制動(dòng)：以相同的順序循環(huán)啟動(dòng)、恒載運(yùn)行和空載運(yùn)行。無停機(jī)時(shí)間。

S6 - 間歇式負(fù)載連續(xù)運(yùn)行：以相同的順序循環(huán)啟動(dòng)、恒載運(yùn)行和空載運(yùn)行。無停機(jī)時(shí)間。

S7 - 連續(xù)運(yùn)行，帶電制動(dòng)：以相同的順序循環(huán)啟動(dòng)、恒載運(yùn)行和電制動(dòng)。無停機(jī)時(shí)間。

S8 - 負(fù)載和速度周期性變化的連續(xù)運(yùn)行：以相同的順序循環(huán)運(yùn)行，先以恒定負(fù)載和給定速度運(yùn)行，然后以其他恒定負(fù)載和速度運(yùn)行。無停機(jī)時(shí)間。

The NEMA motors refer to duty cycle in one of two or three terms: continuous, intermittent or special duty (typically expressed in minutes). IEC breaks it into eight ratings:

S1 - Continuous duty: The motor works at a constant load for enough time to reach temperature equilibrium.

S2 - Short-time duty: The motor works at a constant load, but not long enough to reach temperature equilibrium, and the rest periods are long enough for the motor to reach ambient temperature.

S3 - Intermittent periodic duty: Sequential, identical run and rest cycles with constant load. Temperature equilibrium is never reached. Starting current has little effect on temperature rise.

S4 - Intermittent periodic duty with starting: Sequential, identical start, run and rest cycles with constant load. Temperature equilibrium is not reached, but starting current affects temperature rise.

S5 - Intermittent periodic duty with electric braking: Sequential, identical cycles of starting, running at constant load and running with no load. No rest periods.

S6 - Continuous operation with intermittent load: Sequential, identical cycles of running with constant load and running with no load. No rest periods.

S7 - Continuous operation with electric braking: Sequential identical cycles of starting, running at constant load and electric braking. No rest periods.

S8 - Continuous operation with periodic changes in load and speed: Sequential, identical duty cycles run at constant load and given speed, and then run at other constant loads and speeds. No rest periods.

設(shè)計(jì)類型

Design Types

IEC 設(shè)計(jì)額定值代碼描述了電機(jī)的轉(zhuǎn)速與扭矩特性。IEC 設(shè)計(jì)代碼與 NEMA 設(shè)計(jì)類型幾乎相同，只是字母不同。例如，最常見的工業(yè)電機(jī)是 IEC 設(shè)計(jì) N 電機(jī)，它與 NEMA 設(shè)計(jì) B 電機(jī)非常相似；后者是工業(yè)應(yīng)用中最常見的電機(jī)類型。同樣，IEC 設(shè)計(jì) H 的特性與 NEMA 設(shè)計(jì) C 的特性幾乎相同。沒有與 NEMA 設(shè)計(jì) D 對(duì)應(yīng)的特定 IEC 型號(hào)。

從邏輯上講，IEC 后綴是有含義的。例如，IEC 設(shè)計(jì) N（可視為“正?！迸ぞ兀╇姍C(jī)的扭矩通常與 NEMA 設(shè)計(jì) B 電機(jī)的扭矩相同。IEC 設(shè)計(jì) H（可視為“高”扭矩）的扭矩與 NEMA 設(shè)計(jì) C 的扭矩幾乎相同。

The IEC design rating code describes a motor's speed vs. torque characteristics. The IEC Design codes nearly mirror NEMA Design Types, but with different letters. For example, the most common industrial motor is an IEC Design N motor, which is very similar to a NEMA Design B motor; the most common type of motor for industrial applications. By the same token, the characteristics of IEC Design H are nearly identical to those of NEMA Design C. There is no specific IEC equivalent to NEMA Design D.

Logically the suffix with IEC has a meaning. Say comparing toques of IEC Design N (think of it as "normal" torque) motors in general mirror those of NEMA Design B motors. The torque of IEC Design H (think of it as "high" torque) is nearly identical to those of NEMA Design C.

絕緣標(biāo)志

Insulation designations

IEC 和 NEMA 使用相同的繞組絕緣分類系統(tǒng)。該系統(tǒng)基于材料在不降低或縮短電機(jī)壽命的情況下能夠持續(xù)承受的最高溫度。下表比較了 IEC 和 NEMA 標(biāo)準(zhǔn)允許的溫升（總可接受溫度需加 45°C）。

*請(qǐng)注意，NEMA 沒有 E 級(jí)。

大多數(shù)工業(yè)電機(jī)根據(jù)應(yīng)用情況使用 B 級(jí)或 F 級(jí)絕緣。IEC 和 NEMA 1.00 的服務(wù)系數(shù)額定值幾乎相同；NEMA 1.15 的額定值更高。

IEC and NEMA use the same classification system for winding insulation. It is based on the highest temperature the material can withstand continuously without degrading or reducing motor life. The table below compares temperature rises (add 45°C for total acceptable temperature) allowed under IEC and NEMA standards.

*Note that NEMA has no Class E.

Most industrial-duty motors use Class B or Class F insulation, depending on the application. IEC and NEMA 1.00 service factor ratings are nearly identical; NEMA 1.15 ratings are higher.

千瓦和馬力

Kilowatts & horsepower

這是額定電壓、電流和頻率下的額定軸功率輸出。IEC 使用千瓦 (kW)，NEMA 使用馬力 (hp)。兩者之間的換算關(guān)系為 1hp = 745.7 W = 0.7457kW。

與 NEMA 一樣，IEC 也為標(biāo)準(zhǔn)機(jī)座號(hào)分配相應(yīng)的功率額定值。

在較小的額定值下，IEC 和 NEMA 的千瓦/馬力比較結(jié)果比較流暢，但在較大的機(jī)座號(hào)下，它們的差異可能會(huì)大到在某些設(shè)計(jì)應(yīng)用中引起擔(dān)憂。例如，IEC 115S/NEMA364T 區(qū)域適用于 4 極電機(jī)。其中，NEMA 要求機(jī)座號(hào)的功率為 75 hp，而 IEC 要求的功率為 50 hp。如果尺寸差異可以接受，則降至 NEMA 326T 機(jī)座號(hào)即可滿足所需的 50 hp 功率。如果需要 364T 尺寸，請(qǐng)確保不要損壞傳動(dòng)系統(tǒng)或使用更大功率的電機(jī)負(fù)載。

This is the rated shaft power output at the rated voltage, current and frequency. IEC uses kilowatts (kW) and NEMA uses horsepower (hp). The conversion between the two is 1hp = 745.7 W = 0.7457kW

Like NEMA, IEC assigns comparable power ratings to standard frame sizes.

IEC and NEMA kW/hp comparisons flows smoothly in smaller ratings, but in larger sizes they can vary enough to cause concern in some design applications. An example is IEC 115S/NEMA364T areas for 4-pole motors. Here, NEMA calls for 75 hp in the frame size in which IEC calls for 50 hp. Dropping to a NEMA 326T frame provides the 50 hp needed if the dimensioning differences can be tolerated. If you need the 364T dimensions, be sure not to damage the drive train or load with the higher-power motor.

額定電壓（伏特）

Rated Voltage (Volts)

IEC 34-1 標(biāo)準(zhǔn)要求電機(jī)能夠在額定電壓的 95% 至 105% 范圍內(nèi)以額定效率提供額定輸出。

IEC standard 34-1 requires that motors be able to provide their rated output at their rated efficiency for a voltage range of 95% to 105% of the rated voltage.

效率

Efficiency

IEC 電機(jī)的效率通常以滿載或 75% 負(fù)載表示。此外，電機(jī)上可能還會(huì)標(biāo)明效率等級(jí)（EFF1、EFF2 和 EFF3）。

The efficiency for IEC motors is usually given at full load or at 75% load. Also, an efficiency rating (EFF1, EFF2, and EFF3) may appear on the motor.

服務(wù)系數(shù)（不適用于 IEC 電機(jī)）

Service Factor (not used for IEC motors)

IEC 電機(jī)沒有“服務(wù)系數(shù)”額定值定義。相反，溫升、環(huán)境溫度和海拔高度額定值是通過輸出功率（kW）來定義的。如果需要更高的服務(wù)系數(shù)，請(qǐng)使用更大尺寸的電機(jī)。

IEC motors do not have a "Service Factor" rating definition. Instead, the temperature rise, ambient temperature and altitude ratings are defined via the kW output rating. If an increased service factor is required, use the next size larger motor.

這是銘牌術(shù)語和 IEC/NEMA 比較的簡要指南。IEC 額定值通常比 NEMA 更符合邏輯、更系統(tǒng)、更具描述性。

摘要

隨著市場日益全球化，電機(jī)銘牌的通用語言將使電氣工程師/技術(shù)人員能夠在新的選型、安裝或更換過程中快速理解和識(shí)別他們所處理的電機(jī)類型。

雖然 NEMA 標(biāo)準(zhǔn)適用于北美市場，但世界其他地區(qū)遵循 IEC 標(biāo)準(zhǔn)。如果能夠快速識(shí)別描述電機(jī)尺寸、轉(zhuǎn)速、電壓、物理尺寸和性能特征的關(guān)鍵項(xiàng)目，那么選擇和更換電機(jī)就會(huì)變得容易得多。所有這些信息以及更多信息通常都可以在電機(jī)銘牌上找到。驗(yàn)證 NEMA 是否符合 IEC 或其他行業(yè)標(biāo)準(zhǔn)，能夠在項(xiàng)目現(xiàn)場的任何位置正確使用電機(jī)。

通常，IEC 標(biāo)準(zhǔn)比 NEMA 標(biāo)準(zhǔn)精確得多，它定義了每種電機(jī)尺寸的耐久性和通斷額定值。 NEMA 標(biāo)準(zhǔn)并不那么精確，而且采取了更為保守的方法。

That's a short guideline in nameplate terminology and IEC/NEMA comparisons. IEC rating’s in general follows a more logical, systematic, and descriptive path than those of NEMA.

Summary

As the markets continue to become more global, the common language of the motor nameplate will enable the electrical engineers/technicians to quickly understand and recognize exactly what type of motor they're dealing with during a new selection, installation or replacement procedure.

While NEMA standards are for the North American markets, the rest of the world follows the IEC standards. Selecting and replacing motors becomes a lot easier when you can quickly recognize the key items that describe a motor's size, speed, voltage, physical dimensions, and performance characteristics. All of this information and more is usually available on the motor's nameplate. Verifying conformance of NEMA to IEC or other industry standards would enable you to apply motors correctly anywhere on the project site.

In general, the IEC standards are much more precise than the NEMA standardsx, defining endurance and make/ break rating for each motor size. NEMA standards are not as precise and take on a more conservative approach.

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