NEMA及IEC標(biāo)準(zhǔn)下的電機(jī)銘牌識別（連載三）

#1：制造商類型

NEMA 要求制造商類型，但目前尚無行業(yè)標(biāo)準(zhǔn)。它有時(shí)用于定義單相或三相電機(jī)、單速或多速電機(jī)、結(jié)構(gòu)等?！邦愋汀钡亩x因制造商而異。

以下是一些可能遇到的電機(jī)“類型”：

1. 單相，罩極電機(jī)：啟動(dòng)扭矩最低，成本低，效率低，無需電容器。無啟動(dòng)開關(guān)。用于小型直驅(qū)風(fēng)扇和小型齒輪電機(jī)。

2. 單相，PSC電機(jī)（永久分相式電容電機(jī)）：與罩極電機(jī)應(yīng)用類似，但效率更高、電流更低、功率更大。電路中始終有運(yùn)行電容器。

3. 單相，分相電機(jī)：啟動(dòng)扭矩中等偏低，無需電容器，并配有啟動(dòng)開關(guān)。用于易啟動(dòng)、皮帶傳動(dòng)風(fēng)扇和鼓風(fēng)機(jī)、輕啟動(dòng)泵應(yīng)用以及齒輪電機(jī)。

4. 單相電容啟動(dòng)：分為中等啟動(dòng)轉(zhuǎn)矩和高啟動(dòng)轉(zhuǎn)矩兩種類型，均具有中等啟動(dòng)電流和高擊穿轉(zhuǎn)矩。用途包括傳送帶和空氣壓縮機(jī)。

5. 三相：三相感應(yīng)電機(jī)通常具有高啟動(dòng)轉(zhuǎn)矩、高功率因數(shù)、高效率和低電流。啟動(dòng)時(shí)無需開關(guān)、電容器或繼電器。適用于大型商業(yè)和工業(yè)應(yīng)用。

6. 交流/直流（通用或串激）：使用交流電（60 或 50 Hz）。轉(zhuǎn)速高。隨著負(fù)載增加，轉(zhuǎn)速迅速下降。用于鉆頭、鋸子等需要高輸出、小尺寸，且速度特性和有限壽命（主要是電刷壽命）可接受的場合。

7. 并激和永磁直流電機(jī)：高啟動(dòng)轉(zhuǎn)矩和擊穿轉(zhuǎn)矩。低速時(shí)運(yùn)行平穩(wěn)。用于使用 K 型整流直流電源的恒轉(zhuǎn)矩或遞減轉(zhuǎn)矩應(yīng)用。

電機(jī)也可根據(jù)用途分類：

a. 通用電機(jī)專為機(jī)械負(fù)載和難以啟動(dòng)的負(fù)載而設(shè)計(jì)，包括傳送帶、皮帶傳動(dòng)設(shè)備、機(jī)床、往復(fù)泵和壓縮機(jī)等。它們的軸承可以承受更大的徑向和軸向載荷，其物理結(jié)構(gòu)比其他一些電機(jī)更耐重載。

b. 專用電機(jī)專為某些應(yīng)用而設(shè)計(jì)。例如，暖通空調(diào)電機(jī)主要用于風(fēng)扇、離心泵、小型工具、辦公設(shè)備和其他輕型到中型應(yīng)用。其他類型的有限負(fù)載電機(jī)包括沖洗電機(jī)、危險(xiǎn)場所電機(jī)、農(nóng)場電機(jī)、泵電機(jī)、通用交流/直流電機(jī)、真空電機(jī)等。

一些制造商只是在此處添加型號、日期和序列號以幫助識別。有時(shí)，還會注意到銘牌上顯示其他機(jī)構(gòu)的標(biāo)識，包括 UL 認(rèn)證標(biāo)簽、歐盟的“CE”標(biāo)志和加拿大標(biāo)準(zhǔn)協(xié)會的標(biāo)識。

#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：額定電壓

額定電壓是指電機(jī)設(shè)計(jì)運(yùn)行并達(dá)到最佳性能的電壓。電機(jī)銘牌上定義的參數(shù)，例如功率因數(shù)、效率、扭矩和電流，均指額定電壓和頻率。在非銘牌電壓下運(yùn)行可能會產(chǎn)生不同的性能。

由于線路電壓容易受電力系統(tǒng)負(fù)載條件的影響而隨時(shí)間變化，因此電機(jī)必須設(shè)計(jì)成能夠承受一定的電壓變化。標(biāo)準(zhǔn)感應(yīng)電機(jī)的設(shè)計(jì)允許電壓變化幅度為正負(fù) 10%。因此，當(dāng)供電電壓范圍從 207 V到 253 V時(shí)，銘牌額定電壓為 230 V的電機(jī)可以預(yù)期獲得令人滿意的性能，但不一定理想。

制造商通常會在銘牌上標(biāo)注各種電壓。例如，一臺電機(jī)適用于 230 和 460 V（230/460 V），但可在 208 V 下運(yùn)行。在這種情況下，銘牌上會顯示 208-230/460，并且在 208 V 下性能會下降。

#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：滿載電流 (FLA)

當(dāng)達(dá)到滿載扭矩和馬力時(shí)，相應(yīng)的電流值稱為滿載電流 (FLA)。該值由實(shí)驗(yàn)室測試確定；通常會略微向上取整并記錄為銘牌值。向上取整是為了考慮可能出現(xiàn)的制造偏差以及一些正常的電壓波動(dòng)，這些偏差可能會增加電機(jī)的滿載電流。銘牌上的滿載電流 (FLA) 用于選擇正確的線徑、電機(jī)起動(dòng)器以及必要的過載保護(hù)裝置，以維護(hù)和保護(hù)電機(jī)。

額定滿載電流在銘牌上通?？s寫為“FLA”。相位不平衡、欠壓情況或兩者兼而有之都會導(dǎo)致電流與銘牌上的電流值出現(xiàn)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：額定頻率

這表示電機(jī)的設(shè)計(jì)頻率，單位為赫茲（每秒循環(huán)次數(shù)）。美國、加拿大以及其他一些國家/地區(qū)使用 60 赫茲的電力。電機(jī)的設(shè)計(jì)允許頻率變化為正負(fù) 5%，并且電機(jī)應(yīng)能夠同時(shí)處理電壓和頻率變化。

電機(jī)設(shè)計(jì)為使用變頻驅(qū)動(dòng)器 (VFD) 以不同的速度運(yùn)行；通常會給出頻率范圍。

#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：相數(shù)

在大多數(shù)工業(yè)和商業(yè)設(shè)施中，電力系統(tǒng)（以及相應(yīng)的感應(yīng)電機(jī)）要么是單相的，要么是三相的。三相感應(yīng)電機(jī)的成本效益和效率使其成為所有可用三相電源的自然選擇。

單相電機(jī)可用于小功率需求（小于1HP）以及無法使用三相電源的應(yīng)用（通常最大額定功率為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：滿載轉(zhuǎn)速

電機(jī)的額定滿載轉(zhuǎn)速，即 rpm（每分鐘轉(zhuǎn)數(shù)），是指在施加電壓和頻率保持額定值不變的情況下，電機(jī)在滿轉(zhuǎn)矩條件下運(yùn)行的轉(zhuǎn)速。

感應(yīng)電機(jī)的轉(zhuǎn)速始終低于同步轉(zhuǎn)速，并且會隨著負(fù)載的增加而下降。例如，對于 1800 rpm 的同步轉(zhuǎn)速，感應(yīng)電機(jī)的滿載轉(zhuǎn)速可能為 1750 rpm。對于標(biāo)準(zhǔn)感應(yīng)電機(jī)，滿載轉(zhuǎn)速或?qū)嶋H轉(zhuǎn)速通常在同步轉(zhuǎn)速的 96% 到 99% 之間。這也稱為轉(zhuǎn)差率。

多速罩極電機(jī)和 PSC 電機(jī)首先顯示最大轉(zhuǎn)速，然后顯示轉(zhuǎn)速總數(shù)（例如 3000/3-Spd）。多速分相電機(jī)和電容啟動(dòng)電機(jī)首先顯示最大轉(zhuǎn)速，然后顯示第二轉(zhuǎn)速（例如 1725/1140）。齒輪電機(jī)的額定轉(zhuǎn)速表示輸出軸轉(zhuǎn)速。

注意：“高”效率電機(jī)的額定轉(zhuǎn)速通常高于同等尺寸的標(biāo)準(zhǔn)效率電機(jī)。更高的運(yùn)行轉(zhuǎn)速實(shí)際上會增加離心負(fù)載（例如泵和風(fēng)扇）的功耗。對于離心負(fù)載，功率與轉(zhuǎn)速的立方成正比。因此，轉(zhuǎn)速每提高 1%，功率就會提高 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：同步轉(zhuǎn)速

同步轉(zhuǎn)速是基于旋轉(zhuǎn)磁場的電機(jī)理論轉(zhuǎn)速。它由以下公式確定：

S = (120 x F)/P

其中：

? S = 轉(zhuǎn)速（RPM）

? F = 頻率（赫茲）

? P = 電機(jī)極數(shù)

或者，如果知道電機(jī)極數(shù)，則可以通過下表確定轉(zhuǎn)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：額定溫升或絕緣等級

與電機(jī)壽命相關(guān)的最關(guān)鍵因素之一是電機(jī)內(nèi)部最熱點(diǎn)的最高溫度以及允許高溫持續(xù)的時(shí)間。電機(jī)內(nèi)部最熱點(diǎn)的最高允許安全工作溫度取決于以下因素：

1. 電機(jī)周圍空氣的溫度。這是環(huán)境溫度。電機(jī)額定工作溫度為 40°C (104°F)。

2. 電機(jī)在滿載條件下運(yùn)行產(chǎn)生的熱量。這是溫升。

3. 電機(jī)內(nèi)部所有絕緣材料的耐熱性能。為簡單起見，這些材料分為 A、B、F 和 H 級。

此標(biāo)準(zhǔn) 20,000 小時(shí)壽命溫度等級基于環(huán)境溫度加上電機(jī)運(yùn)行期間產(chǎn)生的熱量。

請記住，電機(jī)的設(shè)計(jì)可承受極高的溫度。例如，B 級額定溫度為 130°C，即 266°F，比水的沸點(diǎn)高 54°C。電機(jī)的設(shè)計(jì)可以承受這種溫度。

絕緣材料可防止金屬與金屬接觸或相間短路相互作用。這也稱為介電強(qiáng)度。它可以限制電壓變化的影響。絕緣系統(tǒng)等級如下：

絕緣等級按字母順序排列，性能更佳。例如，F(xiàn) 級絕緣在給定工作溫度下的標(biāo)稱壽命比 A 級更長，或者在給定壽命內(nèi)，它可以承受更高的溫度。

#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：最高環(huán)境溫度

銘牌上列出了電機(jī)在最大溫升下仍能保持絕緣等級公差范圍內(nèi)運(yùn)行的最高環(huán)境溫度。銘牌上通?？s寫為“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

這表示電機(jī)在達(dá)到其設(shè)計(jì)溫升范圍內(nèi)的最大海拔高度，并滿足所有其他銘牌數(shù)據(jù)。如果電機(jī)在此海拔以下運(yùn)行，其運(yùn)行溫度會更低。在更高的海拔，由于稀薄的空氣無法有效散熱，電機(jī)運(yùn)行溫度往往會更高，可能需要降低電機(jī)功率。并非所有銘牌都標(biāo)有海拔高度等級。

# 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：時(shí)間額定值

時(shí)間額定值或工作制指定電機(jī)在額定負(fù)載下安全運(yùn)行的時(shí)間長度，并指示電機(jī)是否適合連續(xù)運(yùn)行。銘牌上顯示為“CONT”。

標(biāo)準(zhǔn)電機(jī)在額定負(fù)載和最高環(huán)境溫度下的額定工作制為連續(xù)運(yùn)行（24/7）。專用電機(jī)可設(shè)計(jì)用于“短時(shí)”運(yùn)行，即僅需間歇運(yùn)行。

這些電機(jī)的短時(shí)額定值可為5分鐘至60分鐘。NEMA 對短時(shí)電機(jī)的定義如下：“所有短時(shí)額定值均基于相應(yīng)的短時(shí)負(fù)載測試，該測試應(yīng)僅在電機(jī)繞組和其他部件的溫度與測試時(shí)環(huán)境溫度相差 5°C 以內(nèi)時(shí)才開始?！?使用短時(shí)額定值可以減小某些應(yīng)用所需的電機(jī)尺寸、重量和成本。例如，可以選擇安裝額定功率為15分鐘的感應(yīng)電動(dòng)機(jī)，為用于預(yù)潤滑燃?xì)廨啓C(jī)組的預(yù)運(yùn)行油泵提供動(dòng)力，因?yàn)檫@種類型的電動(dòng)機(jī)一次運(yùn)行時(shí)間通常不會超過15分鐘。

其他間歇工作應(yīng)用的例子包括起重機(jī)、軟管、閥門執(zhí)行器等。間歇工作額定功率通常以分鐘表示。

# 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：額定馬力

這表示電機(jī)在額定轉(zhuǎn)速下加載至額定扭矩時(shí)的額定馬力輸出。標(biāo)準(zhǔn)的 NEMA 電機(jī)馬力額定值范圍為1馬力至450馬力。當(dāng)應(yīng)用馬力要求介于兩個(gè)標(biāo)準(zhǔn)值之間時(shí)，通常選擇較大的尺寸。這增加了安全裕度，可以降低電機(jī)的工作溫升并延長電機(jī)的使用壽命。

北美使用的交流電機(jī)通常以馬力為單位。歐洲制造的設(shè)備通常以千瓦 (KW) 為單位。馬力可以使用以下公式轉(zhuǎn)換為千瓦：KW = 0.746 x HP

千瓦可以使用以下公式轉(zhuǎn)換為馬力：

HP = 1.341 x KW

這里還應(yīng)注意馬力和扭矩之間的關(guān)系。扭矩是驅(qū)動(dòng)器向負(fù)載提供的旋轉(zhuǎn)力或扭轉(zhuǎn)力。測量單位為英寸磅或英尺磅。扭矩和馬力之間的關(guān)系公式如下：

馬力 (hp) = [電機(jī)轉(zhuǎn)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

扭矩是驅(qū)動(dòng)器施加給負(fù)載的旋轉(zhuǎn)力或扭轉(zhuǎn)力，以英寸磅或英尺磅為單位。扭矩和馬力的關(guān)系如下：

馬力 = (扭矩 x 轉(zhuǎn)速)/常數(shù)

? 如果扭矩以英尺磅為單位，則常數(shù)為 5,252

? 如果扭矩以英寸磅為單位，則常數(shù)為 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：堵轉(zhuǎn)kVA代碼

交流電機(jī)在全壓啟動(dòng)時(shí)，其線路電流遠(yuǎn)高于其滿載運(yùn)行額定電流。所謂的浪涌電流大小取決于電機(jī)馬力和電機(jī)的設(shè)計(jì)特性。在某些裝置中，這種高電流值可能非常重要，因?yàn)樗赡軐?dǎo)致電壓驟降，進(jìn)而影響其他設(shè)備。

為了定義浪涌特性并以簡化形式呈現(xiàn)，一系列代碼字母根據(jù)浪涌電流范圍（以kVA為單位）對電機(jī)進(jìn)行分組。代碼字母定義了雙電壓電機(jī)的低壓和高壓浪涌值。安裝電機(jī)的電工使用此信息來正確選擇電機(jī)的啟動(dòng)器尺寸。以下是代碼字母名稱列表：

該圖表提供了堵轉(zhuǎn)代碼字母，用于定義電機(jī)啟動(dòng)時(shí)所需的浪涌電流。該圖表按每馬力 (HP) 定義了堵轉(zhuǎn)千伏安 (kVA)，并指出每馬力 (HP) 的浪涌電流每增加一個(gè)字母就會增加。更換堵轉(zhuǎn)代碼更高的電機(jī)可能需要額外的上游電氣設(shè)備來處理更高的浪涌電流。

使用此圖表和工作電壓，可以按照以下公式計(jì)算“跨線啟動(dòng)浪涌”：

200 伏 LRA = 代碼字母值 x HP x 2.9

230 伏 LRA = 代碼字母值 x HP x 2.5

460 伏 LRA = 代碼字母值 x HP x 1.25

安裝人員將使用此公式來確定合適的分支電路保護(hù)等級。

# 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. 

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