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Main transformer capacity calculation for STS Crane system

Created by: cloudy_and_wind at: 7/29/2013 1:09 PM (2 Replies)

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7/29/2013 1:09 PM	Rate (0)
cloudy_and_wind Posts: 5 Rating: (0)	Hi all! I have a project. that is STS crane system for port. My system are 4 motor group. Main Hoist, Trolley, Gantry and Boom.My partner chose transformer for the system. and i have to check. I think some problem. + In crane systemMain motor type choice is continuous S1. But in mechanic calculation the duty is S3. In STS crane, the hoist motor frequently have to increase / decrease speed and braking. I think, when we calculate, we have to calculate is P₂=P_RMS*1.4. + i don'tknow what the calculations were correct or not? Please help me! Caculation file in attachment thanks! Attachment caculation trans.pdf (872 Downloads)
cloudy_and_wind Posts: 5 Rating: (0)	Last edited by: O_Moderator at: 7/29/2013 8:22 PM
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7/30/2013 5:51 AM	Rate (0)
Valli Posts: 262 Rating: (45)	Hi. Lets us understand the difference b/w S-3 and S-4 Duty Cycle first. S3: This refers to operation which consists of a number of identical laod cycles, each comprising a period under constant load and internal. The starting current doesnt have a significant effect on the heat rise. In practise, intermittent periodic duty is a series of on-load and off-load periods in Figure A attached. A number of on-load periods of varying lengths between them are repeated cyclically. The Cyclic duration factor for the whole duty cycle is derived from the equation:- CDF= ∑ tb* 100( in %)/ (∑ tb + ∑ tst) In terms of DIN VDE, the preferred values of cyclic duration factor are 25%. S4: This refers to operation comprising a sequence of identical duty cycles each consisting of a significant run-up tim, a time at constant load and an interval. In practise the CDF in percent, the number of starts per hour and the power ratings e.g. 40%. and hence for S-4 duty your power calculation seems right. Attachment PictureA.JPG (822 Downloads)
Valli Posts: 262 Rating: (45)
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8/4/2013 5:40 PM	Rate (0)
cloudy_and_wind Posts: 5 Rating: (0)	Thanks M Valli! But S3 or S4 duty is not main problem! My main problem is " Main Transformer capacity calculation" . The main transformer power in caculate is 630KVA. In my crane system, i don't known this result is correct or not?
cloudy_and_wind Posts: 5 Rating: (0)
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