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Interactive Start Surge Sharing on Common Supply

IP.com Disclosure Number: IPCOM000035418D
Original Publication Date: 1989-Jul-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 5 page(s) / 113K

Publishing Venue

IBM

Related People

Beer, R: AUTHOR [+2]

Abstract

Described is a microprogrammed control method of sequencing power surges from units sharing a common power source. It allows cost reductions in the power system by avoiding deliberate over-design to cater for the possibility of simultaneous surges caused by uncontrolled powering-on of units. Power-up time is minimized and overloads under every operating condition, including misuse, are rendered impossible. Traditional Sequencing Problems

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Interactive Start Surge Sharing on Common Supply

Described is a microprogrammed control method of sequencing power surges from units sharing a common power source. It allows cost reductions in the power system by avoiding deliberate over-design to cater for the possibility of simultaneous surges caused by uncontrolled powering-on of units. Power-up time is minimized and overloads under every operating condition, including misuse, are rendered impossible. Traditional Sequencing Problems

Total system reliability can be increased and power system (PS) costs reduced by making all the component units of the system share a common power supply. Further cost reductions in the power system can then be achieved by sequencing the power surges of the system units such that they do not overlap. A typical power surge used in this example is an electric motor start current that can be four times greater than the running current. If surge sequencing is adopted, then the common power supply only has to be rated to provide the normal

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running current for (n-1) units plus the surge current for one unit where there are n units in the system. If surge sequencing is not adopted, or if individual unit power supplies are used, then the power system must be rated for n times the surge current. This leads to costly over-design of the supply power rating.

If the power surge exists for a fixed time, measured from initial power-on, then the simplest way to provide sequencing would be to give each unit a unique address within the system, and delay each start from power-on by an amount depending on the unit address. These delays would be increased in increments equal to the maximum duration of a starting surge. There are a number of disadvantages to this simple approach. 1.This system will only work if all units are powered up at the same time. If for some reason a unit is turned on after the others have begun their power-up sequence, then it will start after its address dependent delay and cause a power surge coincident with that of another unit.

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2.The delays must be set at the maximum duration of the start surge. The duration of the starting surge would usually have a large variation. This simple system, therefore, always waits the maximum time to start a number of units and no advantage can be taken of the variation in starting time. 3.If a unit is powered on and off individually with other units up and running in the system, then it must always wait for its address dependent delay to time out before starting whether this is necessary or not. Solution

The invention is a method of sequencing power surges from units sharing a common power source. The method is interactive so that all the problems identified above are overcome. Sequencing is made interactive by having a common I/O line connecting all units sharing the same supply as shown in Fig. 1. Two-way communication is required along this SHARE line so that each unit has the...