Open Transition Transfer Switch In Hospitals

Dear ,

What is your concern ? You need to test LTC monthly ?

For that, you need to have stand by LTC arrangement with bus coup[ler facility. with this, you can test periodically, your critical equipment.

Considering the criticality of hospital emergencies, any how, you require the same.

dear,

can you clarify ....

open transition switches - we can by pass sync. facility. basically, sync. facility is very useful with close transition switches.

Hi Rich,

Some new equipment based on some new switching ideas is coming out. We are looking for applications to test the ideas.

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Thanks,

Mac

I assume that the alternate source of power if an emergency genset, if that is the case, try raising the genset frequency to 60.3 or so, as the genset goes through the switches sync. window the switch should operate, also if there is a utility power failure there is no utility to sync. to, there is a dead buss feature that lets the switch operate, there would be a delay returning to utility after because there is two sourses to sync. If you are using the switches test switch for testing there would be a delay because of sync. issues, this is all normal

Rich,

Normally all critical equipments in the hospitals, where even a 10 seconds drift in power loss will create a problem is backed up with a UPS system, that can catter the load for a 10-15 minutes, where by that time the generator or backup source will switch on and the system is under normal condition.

This is the standard practice followed in industries also. Where you have to have both the UPS with the transfer switches, A UPS cannot supply the desired load for long time, if you design a UPS for long loads then the inital cost of UPS will be very high. Its better you segregate and provide UPS for critical loads for a short duration by which time the transfer supply comes online.

In more critical system you can use a rotary UPS system, where there will be a changeover of supply without any time delay, this system takes care of the delay and supplies the power without any drift. the initial cost is a bit high but better than providing UPS for individual loads.

Amarnath

I do not understand why you cannot prove this during your monthly test.

If you have a power quality analyzer or similar power data recorder on the line, why can't you record the monthly test? Is it that you do not have the power dataloggers? FLUKE or Extech both sell power dataloggers. Just a note, make sure that you purchase a datalogger that has the capability to look at the time interval that you are interested in. Some dataloggers only look at your power line every 5 minutes or so. If you are intested in seconds or milliseconds, you need to make sure that the datalogger has the capability to provide you detail for that time interval.

Some dataloggers just store the analog waveform so you can view it, but do not provide analysis capabilities. You will need to purchase a datalogger that can both store and provide analysis/calculation of the analog waveform.

Some handheld Fluke Meters have limited datalogging storage but do not have the capabilities that a power quality analyzer has.

The power quality analyzer should be able to provide hardcopy data to verify that you meet

Additionally, what is rule of the AHJ and Fire Marshall?

Per the NFPA 101 Life Safety Handbook p348 Section 9.1.2 Electrical Systems and I quote "Where required for compliance with this Code, emergency generators and standby power systems shall comply with 9.1.3.1 and 9.1.3.2.

9.1.3.1 Emergency generators and standby power systems shall be installed, tested, and maintained in accordance with NFPA 110, Standard for Emergency and Standby Power Systems.

9.1.3.2 New generator controllers shall be monitored by the fire alarm system, where provided, or at an attended location, for the following conditions:

(1) Generator running

(2) Generator Fault

(3) Generator switch in nonautomatic position

9.1.4 Stored Electrical Energy Systems.

Stored electrical energy systems shall be installed, tested, and maintained in accordance with NFPA 111, Standard on Stored Electrical Energy Emergency and Standby Power Systems.

NOTE: Per 4.1 in 2005 NFPA 110 and specified in Annex "A" this standard specifies requirements for the EPSS as a complete functioning system in terms of types, classes, and levels. It is not the intent of this standard to recommend the EPSS most suitable for any given application.

You specify 10 seconds as per Table 4.1(b) Types of EPSSs

Type 10 10 second power restoration.

Another question:

Can your existing EPSS combination old and new system fall under the definition specified in Annex "A" as a complete functioning system per the AHJ and the Fire Marshall? Has it been signed off on by AHJ and Fire Marshall?