240V single phase on relay

[ecgworks]

Hello to everyone here!

I have a question relating to Masso relay or any other solution that will work.

I have used the Masso relay to control my coolant flood pump. Simple on-off, controlled by Masso thru Masso relay. The pump is 120V and I use Ground to activate it thru the Masso relay.

I now want to control the on-off of VFD thru relay, whether Masso or another vendor.

My problem is, My input voltage is 240V single phase. If I use the ground to try to control on-off it doesn't work with 240 single phase. Since the machine is grounded to common ground, taking the VFD ground out of connection doesn't work, since the ground is established in many other places.

My thought initially is, Use 2 relay switches on the Masso relay, each carrying a single line of 12oV, so the 2 relays would be activating 240V in unison, and activate both relays with the same Masso control switch?

In mind this should work, but not sure if the Masso switch is compatible, although, from normal on-off usage of the switch, this should be OK.

any input would be appreciated before I fry my Masso

 

[rod]

you should be able to get a dual pole relay,

 

[evermech]

@ecgworks

could you clarify what you are trying to do. You are suggesting that you want to turn the main power going into vfd on or off. I usually use a small motor contactor with a 24v low amperage coil in it to switch larger loads. Or are you just trying to control the spindle motor?

Guy

 

[ecgworks]

added drawing

Will a jumper work?

 

[zombieengineer]

@ecgworks

Some back of the envelop calculations indicate that driving 2 relays from a single Masso output should work but right on the edge for minimum component performance (based on some datasheets: approximately 90% chance that any two relays will both be driven simultaneously from a single output).

The input of the relay board uses opto-isolators however these have quite a large variability in performance (bit of a lucky dip) but manufacturers have a minimum performance limit. If the two inputs have components that are on the performance limit it should still work (just).

Before connecting the mains voltage side test a pair of relays and see if they are both reliably switch. If one works and the other doesn't, swap the "non-functioning" relay with another relay (the "non-functioning" relay would have a low input current gain that "half an output" is not quite enough to trigger the relay).

I hope the above information is helpful.

 

[ecgworks]

Thanks for all your replies.

I'll try it today.

My concern was that Masso having a bad reaction to jumping to optoisolators'

I figured I have the Masso relay so why add another unless I need it.

I'll post the results later today.

 

[ecgworks]

tried it and both relays trigger from the same pin.

Thanks to all.