NEMA及IEC标准下的电机铭牌识别（连载三）

#1：制造商类型

NEMA 要求制造商类型，但目前尚无行业标准。它有时用于定义单相或三相电机、单速或多速电机、结构等。“类型”的定义因制造商而异。

以下是一些可能遇到的电机“类型”：

1. 单相，罩极电机：启动扭矩最低，成本低，效率低，无需电容器。无启动开关。用于小型直驱风扇和小型齿轮电机。

2. 单相，PSC电机（永久分相式电容电机）：与罩极电机应用类似，但效率更高、电流更低、功率更大。电路中始终有运行电容器。

3. 单相，分相电机：启动扭矩中等偏低，无需电容器，并配有启动开关。用于易启动、皮带传动风扇和鼓风机、轻启动泵应用以及齿轮电机。

4. 单相电容启动：分为中等启动转矩和高启动转矩两种类型，均具有中等启动电流和高击穿转矩。用途包括传送带和空气压缩机。

5. 三相：三相感应电机通常具有高启动转矩、高功率因数、高效率和低电流。启动时无需开关、电容器或继电器。适用于大型商业和工业应用。

6. 交流/直流（通用或串激）：使用交流电（60 或 50 Hz）。转速高。随着负载增加，转速迅速下降。用于钻头、锯子等需要高输出、小尺寸，且速度特性和有限寿命（主要是电刷寿命）可接受的场合。

7. 并激和永磁直流电机：高启动转矩和击穿转矩。低速时运行平稳。用于使用 K 型整流直流电源的恒转矩或递减转矩应用。

电机也可根据用途分类：

a. 通用电机专为机械负载和难以启动的负载而设计，包括传送带、皮带传动设备、机床、往复泵和压缩机等。它们的轴承可以承受更大的径向和轴向载荷，其物理结构比其他一些电机更耐重载。

b. 专用电机专为某些应用而设计。例如，暖通空调电机主要用于风扇、离心泵、小型工具、办公设备和其他轻型到中型应用。其他类型的有限负载电机包括冲洗电机、危险场所电机、农场电机、泵电机、通用交流/直流电机、真空电机等。

一些制造商只是在此处添加型号、日期和序列号以帮助识别。有时，还会注意到铭牌上显示其他机构的标识，包括 UL 认证标签、欧盟的“CE”标志和加拿大标准协会的标识。

#1: MANUFACTURER’S TYPE

NEMA requires a manufacturer's type, but there is no industry standard for what this is. It is sometimes used to define 1- or 3-phase; single or multi-speed; construction, etc. The "type" definition varies from manufacturer to manufacturer.

Below are some of the "types" of motors that may be encountered:

1. 1-Phase, Shaded Pole: Lowest starting torque, low cost, low efficiency, no capacitors. No start switch. Used on small direct-drive fans and small gear motors.

2. 1-Phase, PSC (Permanent Split Capacitor): Similar to shaded pole applications except much higher efficiency, lower current and higher horsepower capability. Has run capacitor in circuit at all times.

3. 1-Phase, Split Phase: Moderate to low starting torque, no capacitor and has starting switch. Used on easy start, belt-drive fans and blowers light start pump applications and gear motors.

4. 1-Phase, Capacitor-Start: Designed in both moderate and high starting torque types with both having moderate starting current and high breakdown torque. Uses include conveyors and air compressors.

5. 3-Phase: Generally 3-phase induction motors have a high starting torque, high power factor, high efficiency, and low current. Does not use a switch, capacitor or relay for starting. Suitable for use on larger commercial and industrial applications.

6. AC/DC (Universal or Series wound): Operates on AC (60 or 50 Hz) power. High speed. Speed drops rapidly as load increases. Used for drills, saws, etc., where high output and small size are desired and speed characteristic and limited life (primarily of brushes) is acceptable.

7. Shunt Wound and Permanent Magnet DC: High starting and breakdown torque. Provide smooth operation at low speeds. Used on constant or diminishing torque applications with Type K rectified DC power.

Motors can also be classified by their purpose:

a. General Purpose Motors are designed for mechanical loads and hard to start loads, including conveyors, belt-driven equipment, machine tools, reciprocating pumps and compressors, etc. Their bearings can handle heavier radial and axial loads, and their physical construction is more heavy-duty than some other motors

b. Special Purpose Motors are specifically designed for certain applications. For example, HVAC motors are primarily designed for fans, centrifugal pumps, small tools, office equipment, and other light to medium duty applications. Other types of definite duty motors include wash down, hazardous location, farm duty, pump duty, universal AC/DC, vacuum, etc.

Some manufactures simply add the model, date and serial number here to aid in identification. You will also sometime notice other logos of additional agencies shown on the nameplate, including the UL recognition label, the ‘CE’ mark for the European Community and the Canadian Standards Association logo.

#2：额定电压

额定电压是指电机设计运行并达到最佳性能的电压。电机铭牌上定义的参数，例如功率因数、效率、扭矩和电流，均指额定电压和频率。在非铭牌电压下运行可能会产生不同的性能。

由于线路电压容易受电力系统负载条件的影响而随时间变化，因此电机必须设计成能够承受一定的电压变化。标准感应电机的设计允许电压变化幅度为正负 10%。因此，当供电电压范围从 207 V到 253 V时，铭牌额定电压为 230 V的电机可以预期获得令人满意的性能，但不一定理想。

制造商通常会在铭牌上标注各种电压。例如，一台电机适用于 230 和 460 V（230/460 V），但可在 208 V 下运行。在这种情况下，铭牌上会显示 208-230/460，并且在 208 V 下性能会下降。

#2: RATED VOLTS

The rated voltage is the voltage at which the motor is designed to operate and yield optimal performance. Nameplate-defined parameters for the motor such as power factor, efficiency, torque, and current are at rated voltage and frequency. Application at other than nameplate voltage will likely produce different performance.

Since line voltage is apt to vary over a period of time due to power system load conditions, the motor must be designed to cope with some voltage variations. Standard induction motors are designed to tolerate voltage variations plus or minus 10%. Thus, a motor with a nameplate voltage rating of 230 could be expected to give satisfactory but not necessarily ideal performance when supplied with power ranging from a low value of 207 to a high extreme of 253 volts.

Manufacturers often put a wide variety of voltages on the nameplate. For example, a motor wound for 230 and 460 V (230/460 V) but operable on 208 V. In this case the nameplate would read 208-230/460 and will have degraded performance at 208 V.

#3：满载电流 (FLA)

当达到满载扭矩和马力时，相应的电流值称为满载电流 (FLA)。该值由实验室测试确定；通常会略微向上取整并记录为铭牌值。向上取整是为了考虑可能出现的制造偏差以及一些正常的电压波动，这些偏差可能会增加电机的满载电流。铭牌上的满载电流 (FLA) 用于选择正确的线径、电机起动器以及必要的过载保护装置，以维护和保护电机。

额定满载电流在铭牌上通常缩写为“FLA”。相位不平衡、欠压情况或两者兼而有之都会导致电流与铭牌上的电流值出现偏差。

#3: FULL LOAD AMPS (FLA)

When the full-load torque and horsepower is reached, the corresponding amperage is known as the full-load amperage (FLA). This value is determined by laboratory tests; the value is usually rounded up slightly and recorded as the nameplate value. Rounding up allows for manufacturing variations that can occur and some normal voltage variations that might increase the full-load amps of the motor. The nameplate FLA is used to select the correct wire size, motor starter, and overload protection devices necessary to serve and protect the motor.

Rated full load current is often abbreviated as ‘FLA” on the nameplate. Unbalanced phases, under-voltage conditions, or both, cause current to deviate from nameplate amps.

#4：额定频率

这表示电机的设计频率，单位为赫兹（每秒循环次数）。美国、加拿大以及其他一些国家/地区使用 60 赫兹的电力。电机的设计允许频率变化为正负 5%，并且电机应能够同时处理电压和频率变化。

电机设计为使用变频驱动器 (VFD) 以不同的速度运行；通常会给出频率范围。

#4: RATED FREQUENCY

This indicates the frequency for which the motor is designed in hertz (cycles per second). 60 Hertz power is utilized throughout the United States and Canada, as well as a few other countries. Motors are designed to tolerate a frequency variance of plus or minus 5%, and a motor should be able to handle both voltage and frequency variations at the same time.

The motors designed to operate varying speeds using variable frequency drive (VFD); the frequency range is normally given.

#5：相数

在大多数工业和商业设施中，电力系统（以及相应的感应电机）要么是单相的，要么是三相的。三相感应电机的成本效益和效率使其成为所有可用三相电源的自然选择。

单相电机可用于小功率需求（小于1HP）以及无法使用三相电源的应用（通常最大额定功率为10HP）。

#5: NUMBER OF PHASES

In most industrial and commercial installations, the power systems, and consequently the induction motors, will either be single phase or three phase. The cost effectiveness and efficiency of the three phase induction motor makes it the natural choice for all requirements where three phase power is available.

Single phase motors may be used on fractional horsepower requirements (less than one horsepower) and in applications where three phase power is not available (usually through a maximum horsepower rating of 10 HP).

#6：满载转速

电机的额定满载转速，即 rpm（每分钟转数），是指在施加电压和频率保持额定值不变的情况下，电机在满转矩条件下运行的转速。

感应电机的转速始终低于同步转速，并且会随着负载的增加而下降。例如，对于 1800 rpm 的同步转速，感应电机的满载转速可能为 1750 rpm。对于标准感应电机，满载转速或实际转速通常在同步转速的 96% 到 99% 之间。这也称为转差率。

多速罩极电机和 PSC 电机首先显示最大转速，然后显示转速总数（例如 3000/3-Spd）。多速分相电机和电容启动电机首先显示最大转速，然后显示第二转速（例如 1725/1140）。齿轮电机的额定转速表示输出轴转速。

注意：“高”效率电机的额定转速通常高于同等尺寸的标准效率电机。更高的运行转速实际上会增加离心负载（例如泵和风扇）的功耗。对于离心负载，功率与转速的立方成正比。因此，转速每提高 1%，功率就会提高 3%（1.01³=1.03）。

#6: FULL LOAD RPM

The rated full load speed, or rpm (revolutions per minute) of a motor is the speed at which the motor will operate under full torque conditions when applied voltage and frequency are held constant at the rated values.

An induction motor's speed is always less than synchronous speed and it drops off as load increases. For example, for 1800 rpm synchronous speed, an induction motor might have a fullload speed of 1750 rpm. On standard induction motors, the full load speed, or actual speed, will normally be between 96 and 99% of synchronous speed. This is also known as slip.

Multi-speed shaded pole and PSC motors show maximum speed first, followed by total number of speeds (i.e., 3000/3-Spd). Multi-speed split phase and capacitor-start motors have maximum speed shown first, followed by second speed (i.e., 1725/1140). RPM rating for a gear motor represents output shaft speed.

Note: "High" efficiency motors have usually higher speed ratings than comparable sized standard efficiency motors. This higher operating speed can actually increase power consumption in centrifugal loads (e.g., pumps and fans). For centrifugal loads, power varies as the cube of speed. Thus, a 1% increase in speed will result in a 3% increase in power (1.01³=1.03).

#7：同步转速

同步转速是基于旋转磁场的电机理论转速。它由以下公式确定：

S = (120 x F)/P

其中：

• S = 转速（RPM）

• F = 频率（赫兹）

• P = 电机极数

或者，如果知道电机极数，则可以通过下表确定转速：

#7: SYNCHRONOUS SPEED

Synchronous speed is the theoretical speed of a motor based on the rotating magnetic field. This is determined by the following equation:

S = (120 x F)/P

Where:

• S = speed in RPM

• F = frequency in hertz

• P = Number of poles in motor

Or, if you know the number of poles in your motor, you can determine the speed by the following table:

#8：额定温升或绝缘等级

与电机寿命相关的最关键因素之一是电机内部最热点的最高温度以及允许高温持续的时间。电机内部最热点的最高允许安全工作温度取决于以下因素：

1. 电机周围空气的温度。这是环境温度。电机额定工作温度为 40°C (104°F)。

2. 电机在满载条件下运行产生的热量。这是温升。

3. 电机内部所有绝缘材料的耐热性能。为简单起见，这些材料分为 A、B、F 和 H 级。

此标准 20,000 小时寿命温度等级基于环境温度加上电机运行期间产生的热量。

请记住，电机的设计可承受极高的温度。例如，B 级额定温度为 130°C，即 266°F，比水的沸点高 54°C。电机的设计可以承受这种温度。

绝缘材料可防止金属与金属接触或相间短路相互作用。这也称为介电强度。它可以限制电压变化的影响。绝缘系统等级如下：

绝缘等级按字母顺序排列，性能更佳。例如，F 级绝缘在给定工作温度下的标称寿命比 A 级更长，或者在给定寿命内，它可以承受更高的温度。

#8: RATED TEMPERATURE RISE OR INSULATION CLASS

One of the most critical items relating to the life of motors is the maximum temperature that occurs at the hottest point within the unit and the length of time that the high temperature is allowed to exist. The maximum allowable safe operating temperature occurring at the hottest spot within a motor is determined by:

1. The temperature of the air surrounding the motor. This is the ambient temperature. Motors are rated using a 40°C ambient (104°F).

2. The heat created within the motor due to its operation at a fully loaded condition. This is the temperature rise.

3. The thermal capability of all the insulating materials used within the motor. For simplicity, these materials have been broken into classes A, B, F and H.

This standard 20,000 hour life temperature class is based on ambient plus the heat created within the motor during operation.

Please keep in mind that motors are designed to withstand some very high temperatures. As an example, Class B is rated at 130°C, which is 266°F, or 54 degrees above the boiling point of water. Motors have been designed to withstand this type of heat.

Insulating materials prevent metal to metal contact or interaction of phase to phase shorts. This is also known as dielectric strength. It limits the effects of voltage variations. Insulation System Classes are as follows:

Insulation classes perform better in an ascending alphabetical order. For example, class F insulation has a longer nominal life at a given operating temperature than class A, or for a given life it can survive higher temperatures.

#9：最高环境温度

铭牌上列出了电机在最大温升下仍能保持绝缘等级公差范围内运行的最高环境温度。铭牌上通常缩写为“AMB”。

#9: MAXIMUM AMBIENT TEMPERATURE

The nameplate lists the maximum ambient temperature at which the motor can operate and still be within the tolerance of the insulation class at the maximum temperature rise. It is often abbreviated as "AMB" on the nameplate.

# 10：海拔高度

这表示电机在达到其设计温升范围内的最大海拔高度，并满足所有其他铭牌数据。如果电机在此海拔以下运行，其运行温度会更低。在更高的海拔，由于稀薄的空气无法有效散热，电机运行温度往往会更高，可能需要降低电机功率。并非所有铭牌都标有海拔高度等级。

# 10: ALTITUDE

This indicates the maximum height above sea level at which the motor will remain within its design temperature rise, meeting all other nameplate data. If the motor operates below this altitude, it will run cooler. At higher altitudes, the motor would tend to run hotter because the thinner air cannot remove the heat so effectively, and the motor may have to be derated. Not every nameplate has an altitude rating.

# 11：时间额定值

时间额定值或工作制指定电机在额定负载下安全运行的时间长度，并指示电机是否适合连续运行。铭牌上显示为“CONT”。

标准电机在额定负载和最高环境温度下的额定工作制为连续运行（24/7）。专用电机可设计用于“短时”运行，即仅需间歇运行。

这些电机的短时额定值可为5分钟至60分钟。NEMA 对短时电机的定义如下：“所有短时额定值均基于相应的短时负载测试，该测试应仅在电机绕组和其他部件的温度与测试时环境温度相差 5°C 以内时才开始。” 使用短时额定值可以减小某些应用所需的电机尺寸、重量和成本。例如，可以选择安装额定功率为15分钟的感应电动机，为用于预润滑燃气轮机组的预运行油泵提供动力，因为这种类型的电动机一次运行时间通常不会超过15分钟。

其他间歇工作应用的例子包括起重机、软管、阀门执行器等。间歇工作额定功率通常以分钟表示。

# 11: TIME RATING

Time rating or duty specifies the length of time the motor can operate at its rated load safely and indicates whether the motor is rated for continuous duty. This is shown as "CONT" on the nameplate.

Standard motors are rated for continuous duty (24/7) at their rated load and maximum ambient temperature. Specialized motors can be designed for “short-time” requirements where intermittent duty is all that is needed.

These motors can carry a short-time rating from 5 minutes to 60 minutes. The NEMA definition  for short-time motors is as follows: “All short-time ratings are based upon corresponding shorttime load tests, which shall commence only when the windings and other parts of the motor are within 5°C of the ambient temperature at the time of the test.” By using short-time ratings, it's possible to reduce the size, weight, and cost of the motor required for certain applications. For example, you may choose to install an induction motor with a 15-minute rating to power a preoperation oil pump used to pre-lube a gas turbine unit because it would be unusual for this type of motor to be operated for more than 15 minutes at a time.

Other examples of intermittent duty applications include crane, hose, valve actuator etc. The intermittent duty rating is typically expressed in minutes.

# 12：额定马力

这表示电机在额定转速下加载至额定扭矩时的额定马力输出。标准的 NEMA 电机马力额定值范围为1马力至450马力。当应用马力要求介于两个标准值之间时，通常选择较大的尺寸。这增加了安全裕度，可以降低电机的工作温升并延长电机的使用寿命。

北美使用的交流电机通常以马力为单位。欧洲制造的设备通常以千瓦 (KW) 为单位。马力可以使用以下公式转换为千瓦：KW = 0.746 x HP

千瓦可以使用以下公式转换为马力：

HP = 1.341 x KW

这里还应注意马力和扭矩之间的关系。扭矩是驱动器向负载提供的旋转力或扭转力。测量单位为英寸磅或英尺磅。扭矩和马力之间的关系公式如下：

马力 (hp) = [电机转速 × 扭矩 (lb-ft)] ÷ 5,250

# 12: RATED HORSEPOWER

This represents the rated horsepower output when the motor is loaded to rated torque at rated speed. The standardized NEMA table of motor horsepower ratings runs from 1 hp to 450 hp. When application horsepower requirements fall between two standardized values, the larger size is usually chosen. This adds a margin of safety that will reduce the motor’s operating temperature rise and extend the operating life of the motor.

AC motors used in North America are generally rated in horsepower. Equipment manufactured in Europe is generally rated in kilowatts (KW). Horsepower can be converted to kilowatts using the following formula:

KW = .746 x HP

Kilowatts can be converted to horsepower using this formula:

HP = 1.341 x KW

The relationship between horsepower and torque should also be noted here. Torque is the turning or twisting force supplied by a drive to the load. Units of measure are inch pounds or foot pounds. Torque and horsepower are related to each other by the following formula:

Horsepower (hp) = [Motor Speed ×Torque (lb-ft)] ÷ 5,250

# 13：扭矩

扭矩是驱动器施加给负载的旋转力或扭转力，以英寸磅或英尺磅为单位。扭矩和马力的关系如下：

马力 = (扭矩 x 转速)/常数

• 如果扭矩以英尺磅为单位，则常数为 5,252

• 如果扭矩以英寸磅为单位，则常数为 63,025

# 13: TORQUE

Torque is the turning or twisting force supplied by a drive to the load, measured in inch pounds or foot-pounds. Torque and horsepower are related as shown:

HP = (Torque X Speed)/Constant

• If Torque is given in ft-lbs, the constant is 5,252

• If Torque is given in in-lbs the constant is 63,025

# 14：堵转kVA代码

交流电机在全压启动时，其线路电流远高于其满载运行额定电流。所谓的浪涌电流大小取决于电机马力和电机的设计特性。在某些装置中，这种高电流值可能非常重要，因为它可能导致电压骤降，进而影响其他设备。

为了定义浪涌特性并以简化形式呈现，一系列代码字母根据浪涌电流范围（以kVA为单位）对电机进行分组。代码字母定义了双电压电机的低压和高压浪涌值。安装电机的电工使用此信息来正确选择电机的启动器尺寸。以下是代码字母名称列表：

该图表提供了堵转代码字母，用于定义电机启动时所需的浪涌电流。该图表按每马力 (HP) 定义了堵转千伏安 (kVA)，并指出每马力 (HP) 的浪涌电流每增加一个字母就会增加。更换堵转代码更高的电机可能需要额外的上游电气设备来处理更高的浪涌电流。

使用此图表和工作电压，可以按照以下公式计算“跨线启动浪涌”：

200 伏 LRA = 代码字母值 x HP x 2.9

230 伏 LRA = 代码字母值 x HP x 2.5

460 伏 LRA = 代码字母值 x HP x 1.25

安装人员将使用此公式来确定合适的分支电路保护等级。

# 14: LOCKED ROTOR kVA CODE

When AC motors are started with full voltage applied, they draw line currents substantially greater than their full load running current rating. The magnitude of the so-called inrush current is a function of motor horsepower and the design characteristics of the motor. The value of this high current can be important on some installations because it can cause a voltage dip that might affect other equipment.

In order to define the inrush characteristics and present them in a simplified form, a series of code letters group motors depending on the range of inrush in terms of kilovolt amperes. The code letter defines low and high voltage inrush values on dual voltage motors. The electrician installing the motor uses this information to properly size the starter for the motor. The following is a listing of the code letter designations:

The chart provides the locked-rotor code letter that defines an inrush current a motor requires when starting it. The chart defines the locked-rotor kVA on a per-HP basis and indicates that inrush current per HP increases per letter. Replacing a motor with a higher locked rotor code may require additional upstream electrical equipment to handle the higher inrush currents.

Using this chart and the job voltage, you can calculate ‘the across the line starting inrush’ by using the following:

200 Volts LRA = Code letter value x HP x 2.9

230 Volts LRA = Code letter value x HP x 2.5

460 Volts LRA = Code letter value x HP x 1.25

This is used by the installer to determine the proper branch circuit protection rating. 

声明：

- 文章转载自CEDENGINEERING，由爱泽工业翻译，如有侵权，请联系删除！

- 如有偏颇，欢迎指正！