Is it more reasonable to use high voltage or low voltage for a 315KW motor? ?
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Our company is planning to install several fans, with the motor power ranging from 315 to 355 KW. The design originally called for 6KV high-voltage motors coupled with frequency converters; however, our system operates at only 10KV, so we don’t want to use transformers. We are considering using low-voltage (380V) motors together with frequency converters. But after consulting many manufacturers, it turned out that such motors would need to be custom-made. Therefore, we would like to ask everyone: which approach is more reasonable, economical, and suitable in this case? ? ?
Why not simply consider using a 10KV high-voltage motor?
After discussing with the design institute, it was decided to use motors operating at 10 KV voltage; high-voltage frequency conversion control was not required, and a liquid tank was used for speed regulation. This approach has been in use for many years. You can ask the design institute to prepare several plans for comparison; one of them will have a higher cost
It is recommended to use motors with a 10KV voltage, but using high-voltage frequency conversion results in high costs; other speed control methods can be employed instead.
315-355KW is a size that is neither too large nor too small; it is possible to use low voltage together with a hydraulic coupling for speed control, which results in lower investment costs, though operating expenses are slightly higher. If it is a critical load, better stability should allow for compensation.
Premise: Is this the only fan your company has? If, from a technical standpoint, it is possible to replace them with two or three smaller fans, then why not consider using 3 smaller fans? ? Our company also once had a large fan, and a lot of effort was put into installing it and using it properly, but the results were still not satisfactory. If a problem occurs, the entire system comes to a halt, but with three units, if one fails, it only results in a reduction in production. . .
We already have two here, one in use and one as a backup. Still, thanks to everyone for their participation
If variable frequency speed control is considered, low voltage is the preferred choice
If the load is a fan, I recommend using a 10kV high-voltage inverter. Although the control cost of high-voltage inverters is high, they offer good energy-saving effects; fans can typically achieve 30%–40% energy savings. The investment cost is usually recovered within about 5 years, and such inverters also facilitate precise control over the operation process
You need to provide more information so that the system can give better recommendations. For example, details such as the current configuration of your low-voltage transformer and the load distribution can help the design team consider various options more systematically.
Using 10KV is good; it results in lower operating current, reduces the need for initial investment, and causes less impact on the power grid
I think either use a 10kV motor with an inverter. Or it’s 380V. Using 10kV can reduce the operating current and facilitate power configuration, but custom motors are relatively expensive. There are ready-made frequency converters available. Low-voltage motors and frequency converters are relatively inexpensive, but is there enough load capacity available at low voltage? Moreover, the low-voltage current is relatively high. If the cable is long, the line loss will be severe.
It is recommended to use 10KV motors for energy savings! Economic use.
It is best to use a 10kV high-voltage motor together with a 10kV frequency converter.
The selection rules for the rated voltage of electric motors state that for motors with a capacity of 200 kW or less, low-voltage asynchronous motors should be used； The capacity ranges from 200 to 355 kW; if conditions permit, high-voltage asynchronous motors are preferred ； High-voltage asynchronous motors must be used when the capacity is over 355 kW. High-voltage asynchronous motors are expensive, with costly control equipment, but they offer higher efficiency and power factor. Low-voltage asynchronous motors and their control equipment are cheaper, yet they incur greater losses and have a lower electricity utilization rate. The capacity of domestic Y-series 6kV three-phase asynchronous motors ranges from 220 to 2000 kW; therefore, high-voltage on-site compensation devices are also considered within this range accordingly.
A 10kV motor can be considered, and currently variable-frequency speed control is the mainstream approach; coupled systems exhibit a significant performance gap in terms of speed control compared to variable-frequency systems. It is possible to use domestic variable-frequency drives; moreover, the prices of domestic products vary greatly, so it’s advisable to compare them carefully
10KV motors are more expensive than low-voltage ones and are more difficult to maintain. I think low-pressure systems are easier to maintain, but they have higher losses. Our company uses 10/6 KV for high voltage and variable frequency drives for low voltage.
Can the liquid cabinet have its speed adjusted? Aren’t you worried about it boiling when it’s online for a long time? It seems like the liquid cabinet is a soft starter, right? Although the price is low, the subsequent costs are high and maintenance is troublesome. If speed control is necessary on this side, it is recommended to use high voltage; if high voltage is used, avoid soft starters and consider frequency conversion instead. The cost will definitely be recovered. If only addressing start-stop issues is considered, low voltage is a more cost-effective option, as it can save a significant amount of money.
It is recommended to use high pressure, with various speed control methods available