The content of the invention
The technical problems to be solved by the invention are to propose a kind of ventilation fan, driving can be connect by permasyn motor direct
And save and small volume, and have on predetermined direction of rotation and preferably to start and behavior in service, and cost is relatively low, but can be with
Single rotor-position detecting element need not be set and still have preferably performance, thus reduce cost.
The technical scheme that the present invention solves the technical problem is, a kind of low-power ventilating fan, including:
--- the impeller rotated according to predetermined direction, it is axial-flow type and injection molding;
--- the motor of the direct drive impeller, the number of poles of motor stator is 4 poles or 6 poles or 8 poles, stator around
Group is by regulation around to being access to AC power;Motor rotor is p-m rotor, and its number of poles is identical with the number of poles of stator;The stator
The width of air gap is narrowed in the direction of rotation that each pole lower edge is set between rotor, thus in a free state, each pole of rotor
Axis deflects a sharp angle using the axis of the hithermost pole of stator one as reference along the direction of rotation of setting;
--- with one switch, AC power through winding power from the switch to motor stator;
--- with a control circuit, switched on-off described in control;
It is characterized in that:
--- the number of poles of motor stator is 4 poles, and impeller diameter is not more than 100mm;Or the number of poles of motor stator is 6
Pole, impeller diameter is not more than 130mm;Or the number of poles of motor stator is 8 poles, impeller diameter is not more than 150mm;
--- control circuit;Including detection circuit and by the electric circuit inspection to the signal driving switch it is described to control
AC power inputs the plug-in of the electric current of the winding;The detection includes detecting the feature of the AC supply voltage;
--- the detection also includes the terminal voltage for detecting the winding when electric current and the electric current are zero;
--- the plug-in also comprises the steps:
A) rotor is made to be in assigned position;Rotor is at the position, and rotor permanent magnet field axis is super along the circumferencial direction
Sharp angle described in magnetic field axis when front stator winding is passed through certain directional current;
B) switch is driven, the 1st current impulse is inputted the winding;The current impulse is from the AC supply voltage
1st regulation time delay of one zero crossing starts, and its direction is opposite with the sense of current described in step a);
Once c) the 1st current impulse reverts to zero, the terminal voltage and AC supply voltage, including the end are checked immediately
The time difference of voltage characteristic value and its 1st zero crossing and the zero crossing of AC supply voltage the 3rd;When the terminal voltage characteristic value
When absolute value is more than setting and the absolute value of the time difference and is less than specified time period, the switch is driven, makes the 2nd current impulse
Input the winding;The current impulse is in opposite direction with the 1st current impulse, and relative to the AC supply voltage
3 zero crossings have the 2nd regulation time delay;Subsequently into synchronous operation;And
D) when the absolute value that the absolute value of this feature value is less than setting or this feature value is more than setting and the time
Difference absolute value be more than specified time period when, since step a) repeat said process, and if this feature value absolute value be more than rule
Definite value and the advanced zero crossing of AC supply voltage the 3rd of its 1st zero crossing, then increase continuing for the 1st regulation time delay
Time;If the absolute value of this feature value is less than setting or the absolute value of this feature value is more than setting and its 1st zero crossing
Fall behind the zero crossing of AC supply voltage the 3rd, then shorten the duration of the 1st regulation time delay.
The technical scheme is dexterously utilized:
--- the period that winding current is zero may be present in ventilation fan starting process of motor;
--- when the electric current of the winding is zero, the position of the terminal voltage correspondence p-m rotor of winding and rotating speed.
Therefore, it is possible to which the terminal voltage of winding controls ventilation fan motor when surveyed winding current is zero, especially it starts
Process.Experiment shows, with detect the characteristic value and its 1st zero crossing of the voltage and the zero crossing of AC supply voltage the 3rd when
Between difference be controlled as condition, ventilation fan can be adapted in a wide range from zero load to more heavy duty startup situation, is especially changed
Gas is fanned out to air port in face of the outdoor exhaust of reverse wind direction or even starts the heavy duty startup situation that the reverse wind of cause reverses impeller, more
Reasonably ventilation fan is started, accelerated and operation of pulling in, so as to single rotor-position detecting element need not be set and
Still there is preferably performance, therefore structure simplifies and reduces cost.
The further design of the program is:
It is zero when the duration for shortening the 1st regulation time delay in institute step d), the absolute value of still described time difference
The 1st zero crossing more than specified time period and the terminal voltage falls behind the zero crossing of AC supply voltage the 3rd or its feature
The absolute value of value is less than setting, then after the step a) since said process is repeated step a) every time and step
B) before, first input n current impulse, the n current impulse successively from before the zero crossing of AC supply voltage one the
2nd, 4,6 ... (2n-2) individual zero crossings start, and its direction is opposite with the sense of current described in step a);On n, for first
There is the absolute value that the time was zero still described time difference more than the 1st zero crossing of specified time period and the terminal voltage to fall
The zero crossing of AC supply voltage the 3rd or the absolute value of its characteristic value are less than the situation of setting, n=1 afterwards;If going out again
The now situation, n=2;And so on n is increased by natural number.
Its advantage is:Further increase ventilation fan and start the adapted to loading range of control, be remarkably improved electricity
Motivation detent torque, especially ventilation fan anti-reflective turn the ability started.
Further design one of be:
The terminal voltage characteristic value is that the electric current of the AC power input winding reverts to the winding after zero
1st value of terminal voltage or the 1st extreme value.The former has most fast response, and the latter's detection is more stable.
Further the two of design are:
The synchronous operation is to drive the switch according to the frequency of the AC power, by the AC supply voltage with
Specified waveform puts on the winding;Or when the absolute value of the terminal voltage is in increase and polarity and the AC supply voltage
Polarity it is identical when, the switch is driven immediately, the AC supply voltage is put on into the winding.The former control ratio is simpler
It is single;The latter can relatively accurately make the active force between stator and rotor magnetic flux identical with direction of rotation thus more efficient.
Further the three of design are:
The p-m rotor magnetizes for sine wave, is conducive to more accurately detecting the extreme point and zero passage of the terminal voltage
Point.
Further the four of design are:
Rotor is in assigned position in the step a) includes following process:
A1 the switch) is driven, since the regulation time delay of the AC supply voltage zero crossing, is made and institute in step a)
State the current impulse of sense of current identical at least two and input the winding;During these current impulses revert to zero, check described
Terminal voltage;
A2) if:
If --- after the most end 1 in the current impulse reverts to zero, the terminal voltage duration is providing upper and lower
In the range of limit, the process terminates;
If --- after the most end 1 in the current impulse reverts to zero, the terminal voltage duration is more than in regulation
Limit, it is described regulation time delay increase, since step a1) repeat said process;
If --- after the most end 1 in the current impulse reverts to zero, the terminal voltage duration is less than under regulation
Limit, it is described regulation time delay reduce, since step a1) repeat said process.
Experiment shows, according to above-mentioned control, can reach rotor before starting and compares positioning rapidly and reliably.
Technical scheme and effect will be further described with reference to accompanying drawing in a specific embodiment.
Embodiment
Ventilation fan of the embodiment of the present invention is described in the authorized earlier application CN201110303632.1 of the applicant
Improve and form on the basis of embodiment.
The basic mechanical structure of ventilation fan of the embodiment of the present invention is as shown in figure 1, it inherits Fig. 1 institutes in CN201110303632.1
Show that structure includes:
--- it is fixed on the motor 2 of casing;
--- the aial flow impeller 1 of the motor output shaft rotate counterclockwise is directly connected in, it has 4 blades;Press
Blast requirement, the number of blade can also be 3,5 or 6, but had better not be more than 8, and be as far as possible odd number piece, be made an uproar with reducing vibration
Sound.Impeller is injection molding, diameter 100mm.Impeller should not be bigger, and rotary inertia is preferably as far as possible small, to coordinate motor 2 still less
Big staring torque;
--- motor 2 is inner rotor motor, including stator 100 and p-m rotor 200.
The motor electromagnetism basic structure of ventilation fan of the embodiment of the present invention is as shown in Fig. 2 it is inherited
Structure includes shown in Fig. 2 in CN201110303632.1:
--- rotor 200, is that its section is divided into 4 symmetrical 90 with two orthogonal symmetry axis 4000Sector
And each radial magnetizing is N, S, N, S 4 pole p-m rotors;
--- stator 100 is made up of circular iron core 101 and winding 12 with 4 salient poles;Winding 12 is each in 4 salient poles
Around a coil part with Insulating frame, then by around to being connected in series as 4 poles, and thus produce wearing for 4 poles when being powered
The main flux of air gap more between rotor;
--- gradual change is narrowed the width of air gap in the counterclockwise direction between each salient pole of stator core 101 and rotor 200;Therefore exist
Free state be no power and without outer gas stream and rotational structure it is good in the case of, rotor 200 is attracted by stator core, respectively
The geometrical axis of pole is the permanent magnet flux axis 700,800 for passing through air gap between rotor respectively with the geometry of adjacent stators salient pole
Axis is that to pass through the main flux axis 500,600 of air gap between rotor be reference, one is deflected in the counterclockwise direction less sharp
Angle Ω.It is 5 that the present embodiment, which designs the mechanical angle,0(electrical angle 100).The angle can change with the ratio that gradual change is narrowed, and influence
Detent torque and efficiency.The design can avoid in a free state rotor stay in its axis overlapped with the axis of stator salient poles and
Make so-called " dead point " position that detent torque is zero during energization, the reluctance torque formed, which is also helped, prevents the rotor in operating
Torque is not produced when alternating current zero passage and is stalled;
Main variation compared to structure shown in CN201110303632.1 Fig. 2 is:Hall element 300 shown in figure is cancelled.
Ventilation fan of embodiment of the present invention electromotor control circuit is as shown in figure 3, it inherits Fig. 3 in CN201110303632.1
Shown circuit includes:
--- bidirectional thyristor 4, its main electrode is connected with winding 12 to be followed by toward ac power supply terminal 5;
--- single-chip microcomputer 6, its output circuit 63 is access to the trigger electrode 41 of bidirectional thyristor 4, if output pulse is that triggering is double
Turned on to IGCT 4, AC power half-wave voltage now is to start to put on input winding 12 until the half-wave zero passage terminates,
The pulse current input winding 12 of (synchronous and delayed) corresponding to the voltage.
--- the shaping circuit being made up of resistance 7 and diode 8,9 and 5V dc sources VDD, its input is access to exchange
Power supply terminal 5, output B in the polarity of voltage positive half-wave of ac power supply terminal 5 for 1 negative half-wave when be 0, and export B by 1
I.e. AC supply voltage zero crossing at the time of being changed into 0 or be changed into 1 from 0.Output B is access to the input circuit 61 of single-chip microcomputer 6.
Main variation compared to circuit shown in CN201110303632.1 figures includes:
--- the circuit that former Hall element 300 and its output are access to single-chip microcomputer input is cancelled;
--- the former one end directly connect publicly of winding 12 is changed to connect publicly through resistance 13, the resistance be detect by around
The sample resistance of the electric current of group 12;The converted circuit 621 of tie point of winding 12 and resistance 13 is access to the input circuit of single-chip microcomputer
62, voltage drop of the electric current for passing through winding 12 for checking in resistance 13;
--- the tie point of the main electrode of bidirectional thyristor 4 and winding 12 with publicly between bridging resistance 10,19 connect
Bleeder circuit, resistance 10,19 is connected in series the input circuit 68 that a little converted circuit 681 is access to single-chip microcomputer;It is anti-to input
Reflect the terminal voltage when electric current of winding 12 is zero.
Above-mentioned change-over circuit 621,681 may be designed as transformer isolation clamp circuit:
——1:The tested alternating voltage of 1 primary connection, secondary superposition one is higher than tested alternating voltage peak
Constant DC voltage, so that tested alternating voltage is converted to waveform shown in 31 in similar CN201110303632.1 Fig. 4 or Fig. 7
Unipolarity fluctuation voltage input single-chip microcomputer input circuit, in single-chip microcomputer through A/D conversion i.e. can obtain test cross stream voltage
Instantaneous value.
Certainly, it also can select the chip containing above-mentioned functions and single-chip microcomputer and replace single-chip microcomputer 6 and change-over circuit 621,681.
The plug-in of single-chip microcomputer 6 checks the level of input circuit 61,62 and 68 essentially according to setting procedure, through measurement, ratio
Compared with, differentiate, by output circuit 63 export triggering IGCT 4 pulse.
Basic settings in plug-in:
--- once the level of input circuit 62 reverts to the DC voltage of the clamper, assert the electric current of input winding 12
It is zero, the level of input circuit 68 is used for determining the terminal voltage of winding 12;
--- the assigned position for defining rotor is:With appropriate numerical value and with the polarity of AC power positive half-wave shown in 51 in Fig. 4
Identical constant DC voltage is continuously applied in power-off, the position that p-m rotor is stopped after a period of time of winding 12.Now, forever
Magnetic field axis one sharp angle of the magnetic field axis along the advanced said stator winding 12 of the steering counterclockwise set shown in Fig. 2.
Execution step in plug-in:
A) rotor is made to be in the process of assigned position:
A1) at the time of continuous at least two input circuit 61 is changed into 1 from 0, the output of output circuit 63 pulse after delay t0
Triggering IGCT 4 makes pulse current I0 input winding 12;Once input the electric current of winding 12 by the level identification of input circuit 62
It is zero, checks the level of input circuit 68 to determine the terminal voltage of winding 12;
A2) if:
--- the voltage-duration is in the range of regulation upper and lower limit, and the process terminates;
--- the voltage-duration is more than set upper limit, increases t0, since step a1) repeat the process;
--- the voltage-duration is less than regulation lower limit, t0 is reduced, since step a1) repeat the process.
Once b) input circuit 61 from 1 is changed into 0, from the zero crossing, (each zero crossing is named as AC power electricity successively thereafter
Press the 1st, 2,3 ... zero crossings) the output pulse-triggered of output circuit 63 IGCT 4 after delay t1, make pulse current I1 inputs around
Group 12.
Once being c) zero according to the electric current of the level identification input winding 12 of input circuit 62, input circuit 68 is checked immediately
Level to determine the electric current of winding 12 as zero when terminal voltage v (referring to v1 '~v3 ' in the v1~v6 and Fig. 5 in Fig. 4), bag
Include the time difference 92 of its 1st extreme value 91 and its 1st zero crossing and the zero crossing of AC supply voltage the 3rd;It is exhausted when extreme value 91
To value is more than setting and the absolute value of time difference 92 is less than setting, from the zero crossing trigger t2 of AC supply voltage the 3rd
Afterwards, the output pulse-triggered of output circuit 63 IGCT 4, makes pulse current I2 input winding 12;Subsequently into synchronous operation;And
D) when the absolute value of extreme value 91 is less than setting or is more than setting more than setting and the absolute value of time difference 92,
Above-mentioned all processes are repeated since step a), and if the absolute value of time difference 92 is more than setting and terminal voltage v the 1st mistake
The advanced zero crossing of AC supply voltage the 3rd of zero point, then increase tl;If the absolute value of time difference 92 is less than setting or more than regulation
Value and terminal voltage v the 1st zero crossing fall behind the zero crossing of AC supply voltage the 3rd, then reduce tl;When tl is reduced to zero, still
The absolute value of time difference 92 be more than setting and terminal voltage v the 1st zero crossing fall behind the zero crossing of AC supply voltage the 3rd or
The absolute value of its 1st extreme value 91 be less than setting, then every time it is described repeat said process in step a) after and step
B) before, allowing output circuit 63 to export pulse-triggered IGCT 4 makes n current impulse In input winding 12, the n current impulse
Successively since the 2nd, 4,6 ... (2n-2) individual zero crossings before the zero crossing of AC supply voltage one, and its direction with
The sense of current is opposite described in step a).On n, it is more than for occurring the absolute value of the reduction still time differences 92 of tl to zero first
Setting and terminal voltage v the 1st zero crossing falls behind the absolute of the zero crossing of AC supply voltage the 3rd or its 1st extreme value 91
Value is less than the situation of setting, n=1;If occurring the situation, n=2 again;If the 3rd time there is the situation, n=3;If the 4th
There is the situation, n=4;And so on.
Motor enters synchronous operation, and the essentially identical synchronizing current It of continuous input waveform is had 2 kinds by input winding 12
Mode:
--- first, output circuit 63 is persistently exported by ac power frequency since the pulse-triggered IGCT zero crossing
4 constant conductions, by AC supply voltage to put on winding 12 than more complete sinusoidal waveform;, can also be during light load
Suitable time-delay exports pulse-triggered IGCT 4 again after each zero crossing, and AC supply voltage is applied with defect sinusoidal waveform
In winding 12, so as to reduce voltage to reduce input power.
--- second, when the level to input circuit 68 assert that terminal voltage v absolute value is increasing and pressing input circuit 61
Level assert AC supply voltage it is identical with terminal voltage v polarity when, output circuit 63 exports pulse-triggered IGCT immediately
4, AC supply voltage is put on into winding 12.AC supply voltage and the comparative approach of terminal voltage v polarity are referred to
CN201110303632.1 patent specifications【0066】~【0071】Section (replaces former Hall output level) with terminal voltage v.The party
Formula has more stable Synchronization Control to different loads and avoids step-out, but supply voltage utilization rate decreases.
The waveform of each signal is as shown in Figure 4 and Figure 5:51 be the voltage waveform of ac power supply terminal 5, and 52 be that shaping circuit is defeated
Go out B waveform, 53,53 ' be the waveform for putting on the electric current of winding 12, and 54,54 ' be the terminal voltage v when electric current of winding 12 is zero
Waveform, 55,55 ' for compare AC supply voltage with described in the similar CN201110303632.1 obtained by terminal voltage v polarity
The waveform of L (when L is 1, the output pulse-triggered of output circuit 63 IGCT 4) is exported, 56,56 ' be the output circuit 63 of single-chip microcomputer 6
The waveform of the voltage pulse exported to the trigger electrode of IGCT 4.
The signal waveforms of motor, there is following situation when Fig. 4 is ventilation fan light load of the embodiment of the present invention:
--- output circuit 63 be delayed at the time of input circuit 61 continuous 2 is changed into 1 from 0 output pulse after t0 (see
56) IGCT 4 is triggered in Fig. 3, the pulse current I0 (see in Fig. 3 53) of 2 positive polarity is inputted winding 12.2 pulse electricity
Stream, which reverts to the terminal voltage measured after zero, to be seen 54 in Fig. 3:V1 sections are that the 1st pulse current reverts to the terminal voltage after zero, electricity
The higher and duration is pressed to be more than set upper limit;V2 sections are that the 2nd pulse current reverts to the terminal voltage after zero, smaller and hold
The continuous time in the range of regulation upper and lower limit, shows that rotor is in assigned position, can then start operating;
--- it is delayed at the time of subsequent input circuit 61 is changed into 0 from 1 after t1,56 institutes in the output of output circuit 63 Fig. 4
Show the 3rd square wave triggering IGCT 4, negative pulse electric current I1 (see in Fig. 4 53) is inputted winding 12.V3 sections are that I1 is reverted to
The terminal voltage of winding 12 after zero, its first negative sense since the 1st value 90 rises to extreme point 91, then declines, in AC power
It is positive after (time interval 92) zero passage before the zero crossing of voltage regulation 3 to rise, until being delayed after the zero crossing of AC supply voltage the 3rd
The 4th square wave triggering IGCT 4, makes positive pulse electric current I2 (see in Fig. 4 shown in 56 in t2, the output of output circuit 63 Fig. 4
53) winding 12 is inputted.As 54, V4 sections are terminal voltages that I2 reverts to winding 12 after zero in Fig. 4, V5, V6 sections are synchronizing current It
Revert to the terminal voltage of winding 12 after zero, it is seen that after V4, V5, V6 sections of equal zero passages polarity it is identical with the polarity of AC supply voltage and
Absolute value is in increase;In single-chip microcomputer 6, by plug-in by v4, v5, the v6 section terminal voltage and AC supply voltage shaping circuit
Output B waveform (see in Fig. 4 52) compares, once the two meets same OR gate logic, output L is 1, the output pulse of output circuit 63
(see in Fig. 4 55) triggering IGCT 4, AC power half-wave voltage hereafter puts on winding 12, and corresponding synchronizing current It is defeated
Enter winding 12.
The signal waveforms of motor, there is following situation when Fig. 5 is ventilation fan heavier loads of the embodiment of the present invention:
--- the execution step in plug-in is carried out by the situation of light load first, above-mentioned when heavier loads
Process as shown in Figure 4, even if occurring tl after pulse current I1 reverts to zero is reduced to zero, the absolute value of still time difference 92 is big
Fall behind the exhausted of the zero crossing of AC supply voltage the 3rd or its 1st extreme value 91 in setting and terminal voltage v the 1st zero crossing
It is less than setting, thus restarting to value:At the time of input circuit 61 continuous 3 is changed into 1 from 0, output circuit 63 is exported
Pulse-triggered IGCT 4, makes the complete positive polarity half-wave of AC supply voltage 3 put on winding 12, thus inputs 3 toward winding 12
Individual complete positive polarity half-wave current, after last 1 electric current (not shown) reverts to zero, checks the terminal voltage of winding 12
V1 ' duration in prescribed limit, shows that rotor is in assigned position.Subsequent input circuit 61 from 1 be changed into 0 when
Carve, the 1st square wave triggering IGCT 4, makes the complete negative polarity of AC supply voltage 1 shown in 56 ' in the output of output circuit 63 Fig. 5
Half-wave puts on winding 12, thus inputs 1 complete negative polarity half-wave current In (see in Fig. 5 53 ') toward winding 12, and the electric current is extensive
It is after zero, to check the terminal voltage v2 ' of winding 12 again;At the time of back to back input circuit 61 is changed into 0 from 1, be delayed t1 '
Afterwards, output circuit 63 exports the 2nd square wave triggering IGCT 4 shown in 56 ' in Fig. 5, and AC supply voltage 1 is applied to winding 12
Individual defect bears half-wave, thus toward the input negative pulse electric current I1 ' of winding 12 (see in Fig. 5 53 '), after the electric current reverts to zero,
The terminal voltage v3 ' of winding 12 is checked, it rises to extreme point 91 ' from the 1st negative sense of value 90 ', then declines, in input circuit
61 it is positive after (time interval 92 ') zero passage before (the 3rd zero crossing) at the time of be changed into 1 from 0 rise, and in input circuit 61 by 0
Be delayed t2 ' after at the time of being changed into 1, the 3rd square wave triggering IGCT 4 shown in 56 ' in the output of output circuit 63 Fig. 5, to winding
12 apply 1 defect positive half-wave of AC supply voltage, thus make positive pulse electric current I2 ' (see in Fig. 5 toward the input of winding 12
53’).At the time of subsequently inputting that circuit 61 is all to be changed into 0 and be changed into 1 from 0 from 1, the output pulse immediately of output circuit 63 (see
56 ' in Fig. 5) triggering IGCT 4, by AC supply voltage to be continuously applied than more complete sinusoidal waveform in winding 12, accordingly
Ground is inputted than more complete sine wave synchronizing current It ' toward winding 12 (see in Fig. 5 53 ').
If as shown in figure 5, check terminal voltage v3 ' the still time differences 92 ' of winding 12 absolute value be more than setting and
Terminal voltage v3 ' the 1st zero crossing falls behind the zero crossing of AC supply voltage the 3rd or the absolute value of its 1st extreme value 91 ' is less than
Setting, i.e. explanation load is quite weighed, and needs restarting, and the input after the completion of the step of rotor is in assigned position is made
At the time of 61 continuous 2, circuit is changed into 0 from 1, the output pulse-triggered of output circuit 63 IGCT 4 makes AC supply voltage 2 complete
Whole negative polarity half-wave puts on winding 12, thus inputs 2 complete negative polarity half-wave currents toward winding 12, then back to back
At the time of the 3rd of input circuit 61 is changed into 0 from 1 after delay, output circuit 63 exports the 3rd pulse-triggered IGCT 4, to around
Group 12 applies 1 defect of AC supply voltage and bears half-wave, thus inputs negative pulse electric current toward winding 12, and the electric current is reverted to
After zero, the terminal voltage of winding 12 is checked, continues subsequent process.
Using terminal voltage v the 1st extreme value 91 or 91 in above-mentioned control ' it is controlled as characteristic value.The extreme value was both
Include the extreme value of stationary point form, also include the numerical value of place period end points.It can also use what terminal voltage v energy reliable measurements were arrived
1st value 90 or 90 ' it is controlled as characteristic value, can have and more timely respond, but due to the 1st of terminal voltage v value
Absolute value of the absolute value generally than its 1st extreme value is small, therefore need to accordingly be reduced for contrasting the setting judged.In addition, feature
Value can also be the terminal voltage v of other regulation characteristic times (such as zero crossing of AC supply voltage one) value.
Further, it is also possible to there is following design to change:
--- the number of poles of motor stator and rotor may be designed in 6 poles or 8 poles.Because of synchronous rotational speed reduction, the maximum of impeller
Diameter can accordingly increase:Number of poles is 6 poles, and impeller diameter is not more than 130mm;Number of poles is 8 poles, and impeller diameter is not more than 150mm;
If --- ventilation fan be used for directly to outdoor exhaust, be preferably designed as standard GB/T 14806 described in covering and partition type change
Gas is fanned, for example, set the sideboard of wind pressure type, electrodynamic type or linkage type described in the standard in the air stream outlet of ventilation fan casing
Or shutter.The design coordinates motor still less big staring torque, and the sideboard or shutter are operated in ventilation fan
Shi Zhangkai, is closed during stopping, can avoiding the rotor of impeller reversion motor by outside reversely air stream drives before starting, so that open
Dynamic difficulty.
--- impeller is also designed to turn clockwise, and only needs in design according to description before by used term
" counterclockwise " is changed to " clockwise ".