First, what are the safety precautions?

answer:

1. parked before the fan can not reach out and touch the impeller;

2. After the induction motor power will still exist for a few seconds, do not touch the leads;

3. Note that the maintenance, after the shutdown, the wind wheel in the pipeline gas flow will still be rotated, pay attention to safety;

4. maintenance personnel overhaul, outside cabinet needs guarded;

5. maintenance personnel in the maintenance, if needed power, personnel, clothing / accessories, tools, materials, which are in danger of being sucked fan, we must strengthen prevention.

Second, the fan selection criteria What?

answer:

Selection of high efficiency, small fan, control a wider range of fans to meet an acceptable system performance, efficiency and quality requirements.

Fan operating point should be selected near the fan efficiency, in order to ensure stable operation, to avoid the fan in the surge zone.

To reduce noise, the fan speed must be reduced, choose a larger fan.

VAV system fans, air flow pressure should run longer part load conditions selected.

Fans choose too large, often running the fan zone in a small amount of wind, air pressure difference large, will cause unstable operation and noise pulsating, high noise issue.

Too small fan selection, will cause the fan speed increases, the air leaving the leaves have a higher speed will result in higher noise.

Typically the fan outlet at an average speed of 10-15 M / S.

Forward multi-wing fan: a low speed, low light structure, low noise, good speed performance and price and so on, should be in front when designing air flow and less pressure or low pressure air volume to the preferred fan.

After the fan: high efficiency, low noise, high pressure and strong structure, etc., when the design pressure of the fan should be preferred to a larger fan.

Shell fan: When the pipeline need to be flexible export position, need to reduce the noise outlet pipe or pipe network in the future may have to change the situation should be preferred.

Total pressure curve flat, small steepness, the static pressure of the wind power affect the performance of a wide range of fans for air volume system sensitive to changes in static pressure, need to VAV air volume control of air conditioning units.

Total pressure curve is steep steepness large, static pressure of wind power turbines little effect for a fixed amount of air conditioner, the forward fan motor is not overloaded.

Fan belt drive as far as possible be equipped with 4/6 pole motors.

Third, how to choose the motor?

answer:

Select the motor must comply with the following principles:

When the motor is working, heating temperature should be close to its license, but not more than.

The motor must have a certain overload, to ensure that in the short time overload situations to run correctly.

Motor starting torque should be required to drag the object, only big, not small.

Actual motor current must be less than the rated motor current