110 VDC PSU capable of 100 AMP for 1 second repetitive.
110 VDC PSU capable of 100 AMP for 1 second repetitive.
(OP)
Hi,
I'm looking for information on where i can get a 110VDC PSU that will deliver 100A for a second repetitivley (as required during testing/commissioning?) I am currently pre-commissioning some Hawker Siddeley Switchgear (HSS), the DC Lighning range with NDC 6 circuit breakers, the literature states the closing actuator in the Breakers can demand 100A for up to one second. We have some portable 110VDC batteries on site that arn't really up to the challenge of closing these breakers as much as is required during testing. We are not permitted to use the sub-station UPS batteries for testing/commissioning. These batteries have been used for LV switchgear control circuits and some other HV switchgear control circuits no problem but they are stuggling with these NDC 6 breakers.
After talks with HSS i found the equipment they use but this is £8-9000, i was hoping someone was aware of a cheaper alternative or any purpose designed equipment.
My calcs show a 15kW PSU @ 110V should be able to give 136Amps ish. Please correct me if i am wrong and any suggestions on where i can get this equipmentare greatly appreciated.
Kyle
I'm looking for information on where i can get a 110VDC PSU that will deliver 100A for a second repetitivley (as required during testing/commissioning?) I am currently pre-commissioning some Hawker Siddeley Switchgear (HSS), the DC Lighning range with NDC 6 circuit breakers, the literature states the closing actuator in the Breakers can demand 100A for up to one second. We have some portable 110VDC batteries on site that arn't really up to the challenge of closing these breakers as much as is required during testing. We are not permitted to use the sub-station UPS batteries for testing/commissioning. These batteries have been used for LV switchgear control circuits and some other HV switchgear control circuits no problem but they are stuggling with these NDC 6 breakers.
After talks with HSS i found the equipment they use but this is £8-9000, i was hoping someone was aware of a cheaper alternative or any purpose designed equipment.
My calcs show a 15kW PSU @ 110V should be able to give 136Amps ish. Please correct me if i am wrong and any suggestions on where i can get this equipmentare greatly appreciated.
Kyle






RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Nine 12V lead-acid blocs of (say) 20AH or above should be able handle this duty without significant sag. A 110V charger would be able to be trimmed to provide the correct charging voltage. Your charger needn't be especially large - 5A or so output would be more than sufficient to trickle charge the cells.
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If we learn from our mistakes I'm getting a great education!
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
PS. these batteries are brand new and worked for a couple of days being trickle charged as you mentioned over-night but they seem to be dying quickly!
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
With respect to gel cells. They require serious attention to detail or their imminent failure is guaranteed. You must recharge them immediately,(if not sooner), after discharge or they shed permanent capacity rapidly. Like in hours.
Trickle charging is not what cyclically used gel cells need.
Keith Cress
kcress - http://www.flaminsystems.com
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Something else i should have said originally is with this being a DC board there are two breakers, one for the positive and one for the negative, per circuit (and per close command). The neg. follows the pos. and the pos is closing almost every time and the neg. is not (although it was originally so is not a fault in the closing circuit). This logic is what has lead me to assume it is the batteries that are struggling.
Thanks you for your input, i wonder if its going to have to be some heavier duty batteries and just lump them around?
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Please can you explain what you meant by breaker simulators and what the Test Switches are you mentioned? having trouble thinking what they are?
Thanks, kyle
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Breaker simulator is a box with inputs/outputs to simulate the operations of a breaker. At a minimum it will have a trip coil, a close coil, a 52a contact and a 52b contact. Can have multiple aux contacts, breaker speed times, other features. Easier to program a simulator to trip slow or stick than to have the real breaker be slow or stick.
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Ever think about a step down transformer and a 100A full wave bridge rectifier, fed by a variac? Thats how it's done sometimes if batteries are unavailable and DC is required. Care should be used if you have sensitive protection, but if its just charging breakers, many have universal charging motors.
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Capacitors would help with any battery bank used in pulse applications. It allows the chemistry to 'get up to speed', over some time period rather than instantly.
Back to batteries, can you build a small trailer and conveniently tow it to a test site, or are they inside buildings or otherwise spatially constrained?
For small batteries, small flooded batteries are far(vastly) more robust. Small motorcycle batteries can be very tough. Batteries about the same size as the 8Ahr units you're using would deliver more current in pulse applications than gels.
Keith Cress
kcress - http://www.flaminsystems.com
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
itsmoked, we are inside substations and upstairs to make matters worse, i will look into the capacitor theory but the motorcycle batteries were a good call as it is the only thing a can think is small and heavy duty, though i don't have any experience with batteries to be honest.
Can anyone help with this one, we originally had 8 cells @ 12V 7AH (2 sets in parralel) and changed this to 9 cells @ 12V 7AH (2 sets on parralel), this gave us 118V when brand new and worked a treat for the first day and were about 107V by the end of that day (still working). The Charger output is 110V and therefore after a full nights charge the cells only ever reach 110V, have I damaged/changed the charge of the cells in any way by doing this, i was thinking even at 110V 9 cells would be better than 8? Have i made a fundamental error?
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
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If we learn from our mistakes I'm getting a great education!
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
You are destroying the batteries as you are certainly not quickly recharging them to a fully charged state with less than 124V and possibly you would need more than that.
Can you tell us what exact battery you are using?
Keith Cress
kcress - http://www.flaminsystems.com
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
The exact battery is "YUASA NP7 - 12, 12V, 7AH, valve regulated, lead acid battery", data sheet attached.
Just to let you know i have changed the set up (again) in a bid to share the load on the batteries. I have made up 3 banks in parralel with each bank containing 8 of the above cells in series (so 24 cells in all), i have not had chance to try these yet, i was thinking it may provide more of a buffer (for want of the correct term) and share the stress across more cells??
The charger output is just under 110V as mentioned previous and I did not know that a 12V cells optimum charging voltage was 13.8 otherwise i would not have changed from 8 cells to 9. The battery data sheet attached shows this ( i should have looked at this ages ago) on the last page bottom left at about 20 degrees it is between about 13.4 and 14.8V. Now that I have an 8 cell set up per bank again and a 110V charger, 110/8 = 13.75, do you think that may be it?
I will be back at site tomorrow so am interested to see if this works now, thanks again, this is helping a lot.
Kyle
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Thanks.
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Yes, six cells per 12V battery. Each cell is considered as a 2V cell even though under charge its terminal voltage is about 2.25V. That's where the confusion usually arises!
Bear in mind that with 48 cells (8x 6V blocs) your breaker tripping scheme will be running at a lower voltage than normal because most 110V systems contain 54 cells (9x 6V blocs) and float charge at about 124V. That said it should still be within operating tolerances with 48 cells. Does your 110V supply have an adjustment to allow you to trim the output voltage? I'd try to get that ninth 6V bloc in each string so you are testing under the same conditions as it will see in service.
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If we learn from our mistakes I'm getting a great education!
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Found the trim pot you mentioned after ringing the company that made the charger, charger output is now 124VDC. Added the extra battery back in so we now have two strings of 9 x 12V batteries in parallel. Charged them for a few hours and they work a treat. They seem to sit around 118 - 119 VDC, will they ever reach the charger output voltage of 124V? (full charging time is 16 hours i think) not that it matters i suppose just wondering. They have had a bit of stick today and they haven't failed once so I think it's safe to say problem solved!
Thanks again for your help,
Hope I can return the favour one day!
Kyle
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Keith Cress
kcress - http://www.flaminsystems.com
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Pleased you got it working. From your choice of currency and the hire company you mentioned I guess you're in the UK. If you're up in the north east you can buy me a pint!
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If we learn from our mistakes I'm getting a great education!
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Scotty UK, yeah i work for a North England based firm but am working in London, if im up that way it's my round.
Kyle.
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Bad luck on working in the Smoke, I did it for two years and that's more than enough for this lifetime. I'm a Geordie lad but living among the Smoggies. I think of myself as a missionary in this dark and godless place.
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If we learn from our mistakes I'm getting a great education!
RE: 110 VDC PSU capable of 100 AMP for 1 second repetitive.
Kyle