CN1043001A - Analog measurement technology of operation characteristics of asynchronous motors - Google Patents

Abstract

The invention discloses a kind of technology of analog measurement AC asynchronous motor operating characteristic, relate to the motor characteristic field tests.It is by " asynchronous motor double frequency feed negative-phase sequence analog temperature detecting technology " or " double-freq and double-fed analog thermometry technology for wire-winding asynchronous motors " and a cover measures and calculated with mathematical model realizes.The present invention can make electrical type tests realize all no direct loads, and has saved the burden that tested motor drags direct load, thus overcome take a lot of work, time-consuming, shortcoming such as power consumption is big.The present invention is also very suitable to measuring of large-scale, vertical, separate unit machine operation characteristic.

Description

Analog measurement technology of operation characteristics of asynchronous motors

The present invention relates to a kind of technology that measures the AC asynchronous motor performance.

At present, five operating characteristic that measure AC asynchronous motor are both at home and abroad all implemented with direct load method, and promptly the axle head that goes out at tested motor drags another motor with shaft coupling and implements as load, thus take a lot of work, time-consuming, power consumption.Implement more difficult for large-scale, vertical or separate unit motor, even can't measure.

For many years, people's notice only concentrates in the temperature rise of analogue measurement motor.Indivedual scholars also have pair possibility of simulated determination electric efficiency to carry out comment in paper.Yet, any substantial research and report to analog measurement asynchronous motor operating characteristic do not arranged so far as yet.The test that the analog temperature detecting technology event so can solve a key parameters in the motor, however as the electrical type tests requirement, still can not be completely free of conventional this burden of direct load method.

Purpose of the present invention just is to make electrical type tests to realize all no direct loadizations, thus short form test equipment and operation, saves energy.

The present invention be by " asynchronous motor double frequency feed negative-phase sequence analog temperature detecting technology " or " wound rotor asynchronous motor dual-band and dual-feed intend thermometry " measure data (88108075.6,88108077.2) and mathematical model and approximate hypothesis and utilize easy empty load of motor, the short-circuit test of routine to realize that its method is referring to Chinese patent application::

One, approximate supposition:

1. ac power supply system is constant and symmetrical.

2. the state of saturation of AC induction motor is considered to constant.

3. ignore the damping action of air-gap field and the additional moment that causes thereof.

4. the AC induction motor stator winding is three symmetrical coilings, ignores kelvin effect.

5. the kelvin effect of ignoring the cage rotor end ring.

6. variable loss (comprising stator and rotor copper loss and additional consumption) is approximate thinks with load variations, presses the per unit value conversion of current squaring.

7. motor is when load variations, and its rotating speed is approximate constant, i.e. Ω=C _OnsT, Ω are mechanical angle speed.

8. think main flux φ m and rotor power factor Cos φ ₂Product be constant promptly: φ m ° of Cos φ ₂=C _OnsT.

Two, measure (or calculating) stator resistance γ by zero load, the short-circuit test of asynchronous motor double frequency feed negative-phase sequence analog temperature detecting technology or double-freq and double-fed analog thermometry technology for wire-winding asynchronous motors and routine ₁, stator rated current I ₁, rotor resistance γ ₂, rotor current I ₂, input electric power P ₁, rated speed n, stray loss Ps go out work characterisitic parameter output power P by the mathematical simulation approximate treatment ₂, efficiency eta, power factor (PF) Cos φ ₁, revolutional slip S, torque M ₂, the steps include:

1. try to achieve fixed loss according to the no-load test of routine, i.e. iron loss P _FeWith wind moussing loss P _{F ω}Sum P _Fe+ P _{F ω}

2. according to measuring stator resistance value γ ₁And convert specified standards resistance value γ ₁(75 ℃) and stator famous brand rated current I ₁(design load) obtains stator copper loss

。

3. rotor copper loss

Ask method identical to wound type asynchronous motor and stator copper loss, the mouse-cage type asynchronous machine be calculated as follows:

＝SP _M

S is a slippage in the formula, tries to achieve by the rated speed calculated value.P _MBe electromagnetic power.P _MBe calculated as follows:

P in the formula ₁Be input electric power (direct-reading)

4. get by theoretical derivation:

Mechanical output is

In the formula: m is the rotor number of phases, and P is a number of pole-pairs, ω ₂Be rotor umber of turn, K _W2Be rotor winding coefficient, I ₂Be rotor current.

Can simplify relation by approximate supposition, promptly

P _MX≡I ₂

Rotor current I ₂But directly survey during to wound type asynchronous motor earthquake load, can ask for by magnetic potential balance by the stator current measured value the mouse-cage type asynchronous machine.

5. output power P ₂=P _MX-P _Fw-P _S

In the formula: P _FwBe the wind abrasion

Ps is a stray loss

6. efficiency eta=(P ₂)/(P ₁)

7. power factor ${\mathrm{Cos\phi }}_1=\frac{P_1}{\sqrt{3}{U}_1{I}_1}$

In the formula: U ₁Be stator voltage

I ₁Be stator current

8. torque is tried to achieve: M ₂=(P ₂)/(Ω), Ω is a mechanical angle speed.

9. calculate according to above-mentioned simplification, can obtain characteristic working curve:

Stator current characteristic I ₁=f(P ₂)

Efficiency characteristic η=f(P ₂)

Power factor characteristic Cos φ ₁=f(P ₂)

Revolutional slip characteristic S=f(P ₂)

(press S= Calculate)

Torque characteristics M ₂=f(P ₂)

(press M ₂=(P ₂)/(Ω) calculated)

Embodiment

With JRO ₂71-4 17KW wound rotor asynchronous motor is tested motor, reach " dual-band and dual-feed wound rotor asynchronous motor power supply fictitious load method " with " asynchronous motor double frequency feed negative-phase sequence fictitious load method " and " wound rotor asynchronous motor dual-band and dual-feed counter steer fictitious load method " and test, try to achieve the operating characteristic of this motor every data, list in table 1,2,3 respectively with η, the Cos φ data of trying to achieve with actual load method.By table as seen, two critical quantity η, Cos φ in the operating characteristic that employing the present invention obtains, very approaching with direct load method, its error is in engineering permissible range.Therefore, the present invention can make electrical type tests realize all no direct loadizations, thereby has simplified testing equipment and operation greatly, greatly saves electric energy, is of great value.

Table 1: wound type asynchronous motor is asked for operating characteristic with double frequency feed negative-phase sequence simulation.

JRO ₂71-4 17KW

Table 2: wound type asynchronous motor is asked for operating characteristic with dual-band and dual-feed counter steer simulation.

JRO ₂71-4 17KW

Tested motor nameplate ratings:

P ₂＝17KW U ₁/U ₂＝380/312.6（V）

I ₁/ I ₂=34.1/34.8(A) n=1461 rev/min

Claims (1)

1, a kind of analog measurement AC asynchronous motor method for working properties, it is by " asynchronous motor double frequency feed negative-phase sequence analog temperature detecting technology " or " double-freq and double-fed analog thermometry technology for wire-winding asynchronous motors ", conventional zero load, short-circuit test and a cover measurement and mathematical simulation calculation realize that its method is:

One, do following supposition earlier:

1. ac power supply system is constant and symmetrical.

2. the state of saturation of AC induction motor thinks constant.

3. ignore the damping action of air-gap field and the additional moment that causes thereof.

4. the AC induction motor stator winding is three symmetrical coilings, to ignore kelvin effect.

5. the kelvin effect of ignoring the cage rotor end ring.

6. variable loss (containing stator and rotor copper loss and additional consumption) is approximate thinks with load variations, presses the per unit value conversion of current squaring.

7. motor is when load variations, and its rotating speed is approximate constant, and promptly mechanical angle speed Ω is a constant.

8. think main flux φ _mWith rotor power factor (PF) Cos φ ₂Product be constant.

Two, measure (or calculating) stator resistance γ by zero load, the short-circuit test of asynchronous motor double frequency feed negative-phase sequence analog temperature detecting technology or double-freq and double-fed analog thermometry technology for wire-winding asynchronous motors and routine ₁, stator rated current I ₁, rotor resistance γ ₂, rotor current I ₂, input electric power P ₁, rated speed n, stray loss Ps go out work characterisitic parameter, output power P by the mathematical simulation approximate treatment ₂, efficiency eta, power factor (PF) Cos φ ₁, revolutional slip S, torque M ₂, the steps include:

1. fixed loss, i.e. iron loss P are tested and tried to achieve to the method for no-load test routinely _FeWith wind moussing loss Pf ω sum.

2. measure stator resistance value γ ₁, and convert specified standards resistance value γ ₁(75 ℃) and stator famous brand rated current I ₁(design load) calculates stator copper loss then ,

3. obtain rotor copper loss

A. ask method identical for wound type asynchronous motor and stator copper loss.

B. to the mouse-cage type asynchronous machine by the above-mentioned iron loss P that obtains _Fe, stator copper loss With input electric power P ₁(direct-reading) obtains electromagnetic power P earlier _M, P _M=P ₁-P _Fe- , ask rotor copper loss then , wherein S is a slippage, tries to achieve by the rated speed calculated value.

4. ask mechanical output P _MX, use P _MX=3I ¹² ₂(r ¹ ₂)/(S) (1-S) obtained P _MX, rotor current I ₂Learn:

Directly survey during a. to wound type asynchronous motor earthquake load;

B. the mouse-cage type asynchronous machine is measured stator current, press magnetic potential balance again I ₂Calculate:

$I^1{}_2=\sqrt{\frac{P_{\mathrm{CU2}}}{{\mathrm{3r}}_2}}$

5. obtain output power P ₂, P ₂=P _MX-P _{F ω}-P _s, P _sBe stray loss.

6. efficiency eta=(P ₂)/(P ₁)

7. power factor (PF) Cos φ ₁, ${\mathrm{Cos\phi }}_1=\frac{P_1}{\sqrt{3}{U}_1{I}_1}$

8. M is tried to achieve in torque ₂=(P ₂)/(Ω), Ω is a mechanical angle speed.

9. obtain characteristic working curve:

A. stator current characteristic I ₁=f (P ₂)

B. efficiency characteristic η=f (P ₂)

C. power factor (PF) characteristic Cos φ ₁=f (P ₂)

D. revolutional slip characteristic S=f (P ₂) (press S= Calculate)

E. torque characteristics M ₂=f (P ₂) (press M ₂=(P ₂)/(Ω) calculated)