How to delay motor to start

Status
Not open for further replies.
A

anbm

Senior Member
Four existing motors + some non-motor loads are fed from the same electrical panel. The panel is fed from an ATS (normal source gets power from main service panel and emergency source is fed from standby generator).

When the ATS connects to generator power, we want to start each motors at different time (delay to start), what can be added/modify in field to make this delay starting happen? Among those 4 motors, 2 has VFD controls and 2 via motor starters.

Below article said something about time delay relays, is this type of relay what I need to add and make it work?
Assuming this relay will "talk" to the ATS to know when ATS is on generator power?

 
G

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
If the transition to generator takes long enough that the motor starter or VFD drops out, one solution is to take normally open delayed close relays fed by unswitched power. No ATS signalling required.
That would give the same delays on return to normal power.
Each relay would interrupt either the enable of a VFD or the contactor coil of a motor starter.
 
DrSparks

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
anbm said:
Four existing motors + some non-motor loads are fed from the same electrical panel. The panel is fed from an ATS (normal source gets power from main service panel and emergency source is fed from standby generator).

When the ATS connects to generator power, we want to start each motors at different time (delay to start), what can be added/modify in field to make this delay starting happen? Among those 4 motors, 2 has VFD controls and 2 via motor starters.

Below article said something about time delay relays, is this type of relay what I need to add and make it work?
Assuming this relay will "talk" to the ATS to know when ATS is on generator power?

Click to expand...
What you're talking about already exists as a turnkey solution. It's called load management.

www.electricgeneratorsdirect.com

Generac 7000 50-Amp Smart Management Module SMM

Buy Generac 7000 Direct. Check the Generac 50-Amp Smart Management Module (SMM) ratings before checking out.
www.electricgeneratorsdirect.com www.electricgeneratorsdirect.com

Sent from my BE2028 using Tapatalk
 
A

anbm

Senior Member
GoldDigger said:
If the transition to generator takes long enough that the motor starter or VFD drops out, one solution is to take normally open delayed close relays fed by unswitched power. No ATS signalling required.
That would give the same delays on return to normal power.
Each relay would interrupt either the enable of a VFD or the contactor coil of a motor starter.
Click to expand...
Will it be possible if you can draw a diagram for this?
 
DrSparks

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
anbm said:
Four existing motors + some non-motor loads are fed from the same electrical panel. The panel is fed from an ATS (normal source gets power from main service panel and emergency source is fed from standby generator).

When the ATS connects to generator power, we want to start each motors at different time (delay to start), what can be added/modify in field to make this delay starting happen? Among those 4 motors, 2 has VFD controls and 2 via motor starters.

Below article said something about time delay relays, is this type of relay what I need to add and make it work?
Assuming this relay will "talk" to the ATS to know when ATS is on generator power?

Click to expand...
But to actually answer your question, there are a number of different multi function timer relays out there that have selector switches to configure timing and function. The function you are looking for is a triggered delay on make. You could use a dedicated breaker on your main power panel to detect when there is normal power and then invert that logic to the first time delay relay and connect them in a chain where the axillary contact of the first relay triggers the second, third, etc..

Sent from my BE2028 using Tapatalk
 
DrSparks

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
anbm said:
What is this anyway? :) Looks like it limits to 50A, single phase circuit.
Click to expand...
It's nothing but a wireless relay. There are many options and configurations. it's controlled by load management software which talks to the generator. Not sure what generator you have...

Sent from my BE2028 using Tapatalk
 
Y

yesterlectric

Senior Member
Location
PA
Occupation
Electrician
I assume what is wanted here is actually to have each motor have its own delay and not a general delay for all motors. Also you didn’t specify but I’m assuming that you intend to start all the motors as soon as possible when the generator switches over as opposed to randomly starting motors as needed. Thus, each motor would need to have its own delay relay, most likely, unless you have an overall controller of some sort.

In addition to time delay relays or use of any such functions in the VFD, you probably need to come up with a trigger that causes those time delays to only be in the circuit when the ATS is on generator. Does your ATS have auxiliary dry contacts for use on things like this?

Lastly, how much of an inconvenience would it be if you just simplified your design by having those delays in your system at all times regardless of whether the generator or the utility was supplying?
 
Fred B

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
There is a company I deal with that makes a load management/shedding device that will work on up to 100Amp and 3ph loads. The loads can be staggered with these devices giving different priority to each load. No need for control wires back to ATS. They also have an engineer that will design to your specific needs. These are UL listed products. Made in America. I've gotten into their products when I needed shedding for a larger load than the Generac shedding devises would handle.

Home - PSP Products, Inc.

Commercial & Industrial Surge Protection PSP manufactures a diverse selection of surge protection devices (SPDs) designed to meet the needs of any application. Learn More Generator Load Management PSP is the industry leader in load management systems. Some of our “Industry Firsts” include...
www.pspproducts.com www.pspproducts.com
 
Besoeker3

Besoeker3

Senior Member
Location
UK
Occupation
Retired Electrical Engineer
Won't this or similar work?

RS PRO SPDT Timer Relay, ON Delay, 24V ac 0.3 s → 30h, DIN Rail Mount​

 
H

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
A lot of commercial transferswitches have auxiliary contacts that change when switch position changes, this can also be used to trigger the time delay relays previously mentioned.
 
P

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
anbm said:
Four existing motors + some non-motor loads are fed from the same electrical panel. The panel is fed from an ATS (normal source gets power from main service panel and emergency source is fed from standby generator).

When the ATS connects to generator power, we want to start each motors at different time (delay to start), what can be added/modify in field to make this delay starting happen? Among those 4 motors, 2 has VFD controls and 2 via motor starters.

Below article said something about time delay relays, is this type of relay what I need to add and make it work?
Assuming this relay will "talk" to the ATS to know when ATS is on generator power?

Click to expand...
What is the point of delaying the motors that are on on VFDs?
 
ptonsparky

ptonsparky

Tom
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
Besoeker3 said:
Not sure you are going with that. It is just a component.
Click to expand...
I'm frustrated that every solution to a simple control problem needs to include panel builders or similar. Most of these situations should not require anything but limited outside help.

Can I add that simple component to a CH Pump Panel or insert it into the control of a VFD? I can and would in a heartbeat, then sleep well.
 
Status
Not open for further replies.
Top