What is the difference between a DC fan case and an ordinary fan case? First define 'normal'
Direct answer: 'Ordinary fan chassis' is not a unified motor category. It may refer to an AC fixed-speed model or an AC model equipped with a frequency converter. The two are different in terms of speed regulation capability, power distribution and procurement scope. DC fan chassis emphasizes DC or electronic commutation power solutions. If the purchase list only contains these two names, the supplier may quote prices based on different configurations, making it impossible to compare prices and energy consumption.
Ambiguous names will affect inquiries
The term 'ordinary fan box' often appears in project communication, but it does not indicate whether the motor is fixed speed or variable frequency, nor does it indicate whether it contains a driver or control cabinet. The DC fan chassis also needs to be clear whether it is an EC motor or a traditional DC motor, whether the driver is built-in, and what type of control signal it is.
If the purchase list only says 'normal fan chassis' and 'DC fan chassis', the supplier can only guess the configuration based on experience, and the quotation range may be completely different. Some quotations include the driver, some do not; some quotations are based on fixed-speed motors, and some are quoted on variable-frequency motors. The comparison between price and energy consumption loses its basis. The differences in power configuration corresponding to different box forms are inThere are classification instructions in the Aili industrial fan chassis products , which can be used as a starting point to confirm the configuration range.
The core differences between EC motors and AC motors
AC fixed-speed models can only adjust the air volume by air valve or bypass, and the motor speed basically remains unchanged during operation. AC variable frequency models change the speed through the frequency converter, and the speed adjustment range depends on the matching of the frequency converter and the motor. DC fan cabinets usually use EC motors, and the speed is controlled by the matching driver. The speed control signal can be analog, PWM or communication.
The efficiency difference between EC motors and AC motors is particularly obvious under partial load conditions. When running at full load, the efficiency of AC motors is about 80%, while the efficiency of EC motors is about 90%; at 50% load, the efficiency of AC motors drops to about 50%, while EC motors remain at about 80%. This gap comes from the EC motor using a permanent magnet rotor. The rotor magnetic field is provided by the permanent magnet and does not require stator current excitation, so the rotor loss is greatly reduced. At the same time, the efficiency curve of the EC motor is relatively flat throughout the entire speed range, while the efficiency of the AC motor will drop significantly as the speed decreases.
From the perspective of energy consumption, both AC frequency conversion and DC speed regulation can reduce input power under partial load. You can't just rely on the word 'DC' to judge whether it will save more power than 'normal'. The actual energy saving depends on the load curve, system resistance characteristics and speed regulation strategy. If the system operates at full load for a long time, the benefits brought by speed regulation will be limited; if there are obvious on-duty or partial load periods, the value of the speed regulation solution will be reflected.
Align item by item when comparing
The air volume and external static pressure should be designed uniformly first, and then check whether the overall machine power, noise test conditions, power supply, start-stop and speed adjustment interfaces, and the driver are included in the quotation. When modifying existing equipment, you must also check the air duct flange, foundation size, maintenance direction and control cabinet interface; just because the box can be installed does not mean that the operating point is suitable.
Aligned items include at least: design air volume, external static pressure, power supply conditions, speed regulation range, control signal type, driver installation location, noise test distance, and continuous operation time. Without any one of them, the two plans are not on the same basis of comparison.
Writing method that can be used directly for inquiry
For example, write the requirement as 'Continuous operation under a certain air volume and a certain external static pressure requires two speed adjustments. See the drawing for the installation location and direction of the air outlet.' Then explain whether the original machine is AC fixed speed or AC variable frequency. In this way, each company's quotation corresponds to the same delivery scope, and it is easy to check whether the driver, control line and vibration reduction accessories are missing.
The inquiry form should also indicate the power supply voltage and frequency, control signal type, whether fault feedback is required, the minimum operating air volume, whether the driver is installed in the box, and the direction of the access door. If the original system has a filter, also indicate the filter rating and expected resistance. System end configurationWhen using HEPA/ULPA high-efficiency filters , the initial resistance of the filter and the resistance at the end of use should be included in the calculation of the working point.
How to describe requirements to manufacturers
When communicating with Aili Industrial, it is recommended to provide the existing nameplate, on-site air volume and pressure difference records, air duct diagrams and operating periods, so that the general requirement of 'replacement of ordinary models with DC models' can be converted into work points and control requirements that can be accounted for and accepted.Confirmation of fan box configuration should be based on these actual operating conditions, not just on the product name.
If the project involves clean room ceiling air supply, you can compare at the same timeFFU fan filter unit ; it can be used when multiple devices are managed centrally.The FFU computer group control system realizes zone speed regulation and status monitoring. If the core requirement is machine-level protection of a single process equipment,Equipment-end fan filter units (EFU) may be more suitable in terms of size and installation method. When final filtration and uniform air supply are required at the end of the air duct, you can also consider usingHigh-efficiency air supply outlet (HEPA BOX) . When the process requirements are higher, it can be evaluatedDoes the ULPA ultra-high efficiency filter meet the requirements?
