Vfd with integral contactor?

Sblack

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A friend of mine is looking for a vfd with an integral contactor so that as soon as he starts the motor on his machine he can command an unrelated circuit to either open or close and vice versa (Not sure of the exact operation but it doesn’t matter). i guess he can’t command a relay from one of the phases downstream of the vfd because it will interfere with the vfd performance. Does such a thing exist? Is there name for this feature that we could search for? My google fu has not been successful.
 
the DCM function acts much like a contactor in regards to being able to control the VFD from control switches
most VFD's will also have multi-function circuits
the multi-function circuits can be normally open, normally closed and also can be controlled by serial port connections
 
Most VFDs have a programmable relay available to signal some event.

Here is an example of the events that the relay can be programmed to signal. These came from one of my VFD manuals.
00: AC Drive Running
01: AC Drive Fault
02: At Speed
03: Zero Speed
04: Above Desired Frequency (P3.16)
05: Below Desired Frequency (P3.16)
06: At Maximum Speed (P0.04)
07: Over Torque detected (P6.08)
08: Above Desired Current (P3.17)
09: Below Desired Current( P3.17)
10: PID Deviation Alarm
11: Heatsink Overheat Warning (OH1)
12: Soft Braking Signal
13: Above Desired Frequency 2 (P3.20)
14: Below Desired Frequency 2 (P3.20)
15: Encoder Loss
16: PID Feedback Loss Warning
 
You can't command a relay from one of the phases. Almost all VFD's have a programmable relay integral to the VFD with outputs that are NC/NO, some have several outputs either relay or solid state triggers. The limiting factor is the current and voltage that they can handle, so they are more for low level signalling or switching function. As noted above they can be programmed to trigger for different functions. Also VFDs keep a log of many functions like hour meter.

The other alternative is to have a relay trigger the run input and also use as a trigger say for a coolant contactor or use an input on the relay for the other operation desired. This typically requires a separate low voltage power source, many different ways to do it. If you have specifics as to what he wants the contactor to operate, then can provide several options.

V1000 trigger outputs.jpg
 
It's not advisable to hang any circuit on the output of a VFD that would be opening and closing since this can cause voltage overshoots that can damage the transistors in the output stage. Motor loads should be permanently wired in.
-Mark
 
Best to use internal relay, but a relay with correct coil voltage connected across 2 motor lines also could work.

A 240 vac coil will only draw milli-amps and should work fine.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
A relay's and contactor's coil needs a fixed voltage with typically a 10% +/- range and is designed for either AC or DC, the output of the VFD is PWM and will not operate a coil. It would probably fail very quickly feeding it a PWM voltage. Although a relay/contactor may close at a lower voltage then it is speced at, it will lead to premature failure of the contacts due decreased contact pressure and faster deterioration of the contacts.
 
If you don't like the looks of anything else, they sell RIB relays that have current sensing coils you could run one of the legs of the output from the VFD through. Just adjust the Rib for the current draw you've got with the main motor running & use those contacts to run the other thing.
Made by Function Devices, here's an example that google brought up quick, https://www.functionaldevices.com/products/building-automation/details/RIBHX24BA/
I've used these for lots of things over the years.
 
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