Power outage

Status
Not open for further replies.
I'm confused

I'm confused

tdjs said:
The starters are controlled by start-stop buttons in one loaction.The UPS would be located ahead of the stop buttons and circuit breaker that feeds the control switches.Which in turn only is actived when power is off.
Click to expand...

Then

The push-pull and on-off switch would not work because there are 8 start-stop buttons for each fan control by one control power source.Thats where a UPS could keep all the holding coil energized for each of the 8 fans motor starters. This is only going to be used for very short power outage under a minute.Will it still work?
Click to expand...

Now I really don't understand what's going on.
 
Phase monitor

Phase monitor

We use phase monitors for this type of installation. Use of hand/off/auto selector switches in conjunction with the start/stop buttons will allow for manual or auto restart. The best protection would be one monitor for each fan. The alternate would be using one monitor as an input to a Pico type controller or low end PLC. Programing would allow for staggered starts. Do not allow to much time to elapse from Fan 1 to Fan 8 as the latter will be rotating in the wrong direction at start.
 
Why don't you just use manual motor starters or mechanically held contactors if you are controlling them remotely.

Or you could put a latching relay ahead of the coils if you don't want to change all of the starters. Latching relays have two coils, one to close the relay and one to open it. Loss of power does not change the state of the contacts.
 
Lets get this straight...

You have one 480/120 control transformer providing 120 volt control power to start and stop 8 individual 480 volt motors...and....

Each motor can be started and stopped individually with no effect on the other motors (other than E-stop).

Using a individual (momentary contact) start button to energize the individual starter relay.

Using a individual (normally closed) stop button to break the control power to the individual starter relay.

Using a (normally open) auxiliary contact on each individual starter to provide a holding circuit on the individual starter relay once it's energized.

The (maintained break) E-Stop buttons are wired in series with the common 120 volt control power (primary) so that if any E-stop contact opens, control power to all the starters is cut out and all the motors stop.

Is that how the system is wired (at present)?
steve
 
power outage

power outage

Hillbilly, All the items you ask about fits the system.Another question,is there an alarm system I can use to report a power outage over 5 minutes or more by using a phone line tied in the system to notifly the company personel after business hours? Some body has to come to check to see if the tarp is ok.
 
I had a desalination system that was dropping out when the POCO had "power bumps" of less than a second.

We set up the controls to run off a 120 Volt generator that was driven by a manually started motor.

If the power was off for less than a couple of seconds, the inertia of the motor/generator was enough to hold the control circuit relays. If it was off for five seconds or so, the controls dropped out.
 
keep starters closed

keep starters closed

to oringal post . you can use latching relay. you need control power to close and control power to open . you would have to examine your operation to see if this method would work for you safely.
 
tdjs said:
...Another question,is there an alarm system I can use to report a power outage over 5 minutes or more by using a phone line tied in the system to notifly the company personel after business hours? Some body has to come to check to see if the tarp is ok.
Click to expand...
http://www.sensaphone.com/index.html
http://www.flowlineoptions.com/remote-monitoring.html

The links above are a couple that I ran across from internet searches. There are many such systems available from various manufacturers. It's up to you to find the one that's right for you and your application... but perhaps the hardest part will be finding or adapting a system to report the problem a specified time after the event occurs.
 
Just a thought...
You can replace each momentary contact start (push) button and normally closed stop (push) button for each motor with a single, 2 position (on-off) switch and solve your problem.

You won't need to use the auxiliary holding contact on the starter, just wire the control (hot leg) power in series thru the E-Stop buttons, thru the on/off switch and directly to the motor starter relay.

All of your E-Stop buttons will need to be "detention" type, which means that they lock into position. You push the button in to stop the motor and you have to pull the button back out manually to re-start.

Place the E-stop buttons in series in the primary control circuit and use that output to supply common power to the the on/off switches. Wire thru each switch to each starter individually to operate the starter coil (solenoid). If you push a E-stop, the control voltage to the starter coils will be cut and cause them to drop out and the motors will stop.

Remember this... If you reset the E-stop (pull the button back out), all the motors will automatically re-start.

What you're doing is hard wiring the control system through manual "detent" switches and eliminating any "holding circuits". If the circuit is closed (switch turned on) the motors will run until they are manually turned off. If the utility power "blinks" or goes off, the control circuit will not drop out.
When the power comes back on, the motors will re-start automatically.

Make sure that all the personell that works with this equipment understands the changes and how the system operates.

I assume that your motor starters have individual over load protection that mechanically opens the starter (motor) contacts and have to be manually reset. If they are somehow interlocked with the existing holding circuit, some other changes will have to be made.

I have used this procedure several times in the past to control a bank of AC motors.
Again, just a opinion.
You be the judge as to the safety of your installation.
hope this helps
steve
 
hardworkingstiff said:
hillbilly,

Although you said this much more clearly, I thought this is what hockeyologist2 and I were discussing on page 1.
Click to expand...

Correctomundo!
I've slept since I read the first page.
Old age......If I would have thought that I'd live this long, I'd have taken better care of myself.
steve
 
hillbilly said:
Correctomundo!
Old age......If I would have thought that I'd live this long, I'd have taken better care of myself.
steve
Click to expand...

I'm starting to feel that way myself. Sad part is I'm not that old (54 in December).

To all of you younger guys. It really does pay to eat right, exercise, and don't drink too much, and just forget about cigs.
 
starters on

starters on

Back to the original question of "I need to know how to keep motor starters on when there is a loss of power during an electrical storm..." You should not. Unless you live in an area where all three phases drop out at one time consistantly, you risk a very real threat of single phasing these motors. Using latching relays or manually held control circuits will guarantee motor failure. Auto restart should only occur if and when the line voltage to your motor starter(s) is stable, not when you have control power. Don't count on your typical thermal overoads to protect your motors from phase loss or low voltage.

Notification of a problem can be accomplished by using inexpensive home securtiy systems that can place phone calls to a series of numbers. Simply provide the required normally open dry contact via your control circuit and add a phone line.

Another option is to visit your local Pivot dealership. They offer wireless options that with a little imagination can be used almost anywhere. They allow for internet and/or phone control and notification. Yes, it costs but you can't build one for what they can sell it to you at retail.

OSHA should not be a problem if you have meet NEC requirements.
 
I know some of the new "smart" starters have the ability to return to the state in which they were (either on or off) when the power returns, but this would require a chagneout of the existing equipment starters. Also, the remote alarm should be pretty easy to accomplish as well.

I would highly recommend that you contact the local Allen Bradley rep. I am confident that they would pretty much engineer the whole thing for you for free, as long as you were buying the parts, pieces, and what not from them. They have quite a bit of resources they can draw on.
 
ptonsparky said:
"Unless you live in an area where all three phases drop out at one time consistantly, you risk a very real threat of single phasing these motors".

Good point. Single phasing a motor is not good. I don't ever remember seeing the loss of just one leg of 3 phase from the utility. Is it common?
Granted...a holding circuit on the motor starters adds more protection for the motors, especially if they're going to be running un-attended ...but...the OP is trying to eliminate nusiance tripping.
I can see where damaging (and losing) the motors because of single phasing could cause some serious and expensive down time, so using a holding circuit with a alert system is probably a better idea. Unless the time span between getting the alert and someone showing up to restart the motors would be too long to prevent damage to the product.
It's up to the OP to consider all of the pro's and con's. I was just giving one way to do it.

"Using latching relays or manually held control circuits will guarantee motor failure".

guarantee?

"Don't count on your typical thermal overoads to protect your motors from phase loss or low voltage".

low voltage? why you think?
It shouldn't be a big problem to automatically detect phase loss and cut the control power to the starters.

"Simply provide the required normally open dry contact via your control circuit and add a phone line".

Normally open? How does that work with no power?

ptonsparky...I see that you're from Nebraska, so I assume that you have experience with this type installation? I'd like to learn more...I'm always curious.
steve
Click to expand...
 
Yes, loosing one phase is common enough that latching in the control circuit is not a good idea. Learned that from personal experience. Hawks and squirrels are notorious for blowing just one fuse at the pole mounted transformer bank. Monitoring might be okay if the response time is less than a minute. I have never stood by and timed a motor that is single phasing until it failed. That time would change if it is running or starting. Phase loss and low voltage protection is not hard to get and relatively inexpensive. Symcom and TimeMark are just two that I know.

Don't tell my competitors but I have been using this setup to restart irrigation wells that are on utility "control" for over twenty years. No getting up in the middle of the night to restart wells, some of which can be 20 to 30 miles away, plus my customers don't loose $3500 motors and watering time.

The security system requires an input to call, normally closed may be the best in this case. I stand corrected.
 
Status
Not open for further replies.
Top