REMOTE START / STOP FOR LVR MOTOR CONTROLLER FIRE PUMP

[BlackJackJacques]

Gang, I have a question if such an animal exists, at least exist without the complication of a PLC, etc. The AHJ (USCG) s requiring that the fire pumps be outfitted with LVR controllers for obvious reasons. The existing plant uses LVP types but with additional remote start/stop from two manned locations as well as indication and pressure gauges at those remote locations. The AHJ is stuck on the LVR language and insists we revise to LVR. While changing LVP to LVR is simple enough, I would also have to remove the two remote start/stop features as the maintained switches would all be in parallel with the local - so a closed switch at one location would prevent stopping at the local location or the other remote station. Ideally, we move to the LVR configuration but still have the ability to also start/stop from these other two remote locations Seems that someone would have come across this issue before and I'm hoping someone could point me to a simple controller solution.

Thanks in advance

 

[waross]

Low Voltage Release is not compatable with maintained switches.
Momentary stop buttons woll all be in series.
Momentary ztsrt buttons will all be in parallel Nd in parLlel with the sealing contacts


--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[BlackJackJacques]

Waross - Thank you for your comment. I think I could have framed my question better. OK, my understanding of LVR & LVRE both mean restart upon resumption of power. The typical LVR circuits apply maintained (non-momentary) switches to either engage a contactor or across the line (LVRE for small motors). LVP-types applies the hold-in or latching circuit, requiring re-press by the operator. I'm confused by your statement that Low Voltage Release is not compatible with maintained switches - I assume you meant LVP is not compatible with maintained switches. SO, to better reframe my question:

Is there an industry wide means of incorporating remote start/stop provisions for a LVR controller without resorting to the complication of a PLC or similar. Say another remote station to provide Start/Stop in addition to local Start/Stop (at the controller)?


Thanks again

 

[xnuke]

If you had two three-way switches and one four-way switch, you could wire the three switches the way you would wire a lighting circuit controlled from three places. They are available as products suitable for industrial use.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[BlackJackJacques]

Yes, thanks - the residential solution with the "traveler" conductor did cross my mind. I came up with another means that would allow us to reuse the existing momentary switch as the local and two remote stations (with just some simple rewiring) by employing a mechanical latching relay, dual coil and locating it at the controller. That way, we retain the ability for anyone to turn on or off while still retaining the LVR function! Thanks so much gang!


Best

Jim

 

[waross]

The two MOST BASIC motor control circuits are two wire control and three wire control.
TWO WIRE CONTROL restarts automatically on resumption of power.
THREE WIRE CONTROL is compatible with multiple control locations but will not restart automatically on resumption of power.
For automatic restarting and multiple control locations, use a latching relay and multiple latch and unlatch push buttons.
Alternately, You may consider powering the controls from a UPS so that the contactor is held in during a power failure.
This approach will allow the use of Emergency Stops.
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[BlackJackJacques]

Thanks Waross and concur. The mechanical latching relay solution is what we will use to provide us with LVR (TWO WIRE CONTROL) service while permitting re-use of the two existing remote stations controls. Thanks for your help!


Best

Jim

 

[FacEngrPE]

Fire pump controls need to be type listed, unless your AHJ has provided a special dispensation.
See National Electric Code Article 695 Fire Pumps See also NFPA 20-2019, Standard for the Installation of Stationary Pumps for Fire Protection.

 

[wayne440]

This is a marine application, if I am reading the original post correctly.

 

[BlackJackJacques]

Yes, marine application and Coast Guard is the AHJ. Requirements are provided in 46 CFR Sub J and no specific listing requirements identified for fire pump motor controllers. Yes, certain construction requirements wrt branch feeders, breakers, etc, but nothing governing controls. That being said, the solution and mods to the existing LVP controllers applies a two coil mechanical latching relay to drive the M coil - making it simple to provide remote start/stop.

Thanks

 

[waross]

I would consider a hand-off-auto switch between the latching relay and the main contactor.
When the latching relay fails you can put the fire out and then fix the latching relay.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[FacEngrPE]

So afloat you must do something I would never consider ashore.

https://www.ecfr.gov/current/title-46/chapter-I/subchapter-J/part-111/subpart-111.70[/URL]]46CFR111.70-3 Motor controllers and motor-control centers.
Low-voltage release. Each motor controller for a fire pump, elevator, steering gear, or auxiliary that is vital to the vessel's propulsion system, except a motor controller for a vital propulsion auxiliary which can be restarted from a central control station, must have low-voltage release if automatic restart after a voltage failure or its resumption to operation is not hazardous. If automatic restart is hazardous, the motor controller must have low-voltage protection. Motor controllers for other motors must not have low-voltage release unless the starting current and the short-time sustained current of the additional low-voltage release load is within the capacity of one ship's service generator. Automatic sequential starting of low-voltage release controllers is acceptable to meet this paragraph.

 

[BlackJackJacques]

FacEngrPE: Existing unit and existing application was for Sub L OSV. We converted to Sub H Passenger - however, 46 CFR 111.70-3 applies in either case. Existing the fire pump controllers were LVP, however, they included two additional start/stop stations (remote) at the ECC & Bridge, in addition to local. Also at those stations are motor run indication lamps & water pressure gauges. Manning is full time machinery room. Our initial argument was that LVR would present a hazard should the fire hose bale inadvertently be left open - serving to flood the compartment. We believed we met the performance intention of 111.70-3 because of the two remote stations w/indication. Prior classing was ABS ACC who felt like us that the LVP w remote start stop, etc was sufficient. However, CG was stuck on the LVR language and was OK if in doing so, we removed the two remote stations. I wasn't thrilled in giving up start/stop at the two remote stations, and thus my inquiry and the decision to employ the two coil latching relay in the motor start circuit. I guess we have our cake and can eat it too! Thanks

 

[FacEngrPE]

This is a very good example of codes needing to be fit for purpose. It is also a good example of why mixing codes does not work.

The electric requirements of 46CFR works with IEEE 45 Recommended Practice for Electric Installations on Shipboard, not the National Electric Code.

I had to work an application of this shipboard standard set once, and quickly found I needed a specialist in that code set to review all of the work.

 

[BlackJackJacques]

FacEngrPE: IEEE 45 is IBR is IBRed into 46 CFR Sub J as is the NFPA 70 (NEC). Mostly they all work together, although can be circuitous at times, but the biggest conflict comes with the interpretation and enforcement. In the case above of the LVP v. LVR, I believe that the CG lost perspective of the performance intentions of the regulation and despite given latitude to interpret under the equivalency provisions of that same subchapter, they were lazy and relied on the written word. Other complications also come into play, including that CG plan review has since been privatized to contractors - folks that are not familiar with the evolution ( the why) of the regs.