Contactor Overload Relays on 2 phases

Peter from Holland · Jan 13, 2022

I have a contactor overload relay Telemecanique LR2 D13 1.6 to 2.5 Amp
It is protecting a 220 V 2Ph circuit board to drive a DC motor
We measure a load of 1.8 amps with a clamp on At least clearly below 2 amps
But setting the device at 2 amps it still trips after some time

That might indicate a bad device
Orrrrr
Does it only work properly with 3 ph connected ???
Reason I doubt is this line on RS online for a Schneider equivalent

This range of mini thermal overload relays feature compensated and phase failure sensitivity,

The phase failure sensitivity makes me wonder

As a solution we will try to put 2 heaters in serie to see if that works

Peter

TDegenhart · Jan 13, 2022

Phase loss construction of the OL could be your problem. Since you only need two poles, route one leg back through the third OL pole so that the OL sees current on all three legs.

Tom

Peter from Holland · Jan 13, 2022

TDegenhart said:
Phase loss construction of the OL could be your problem. Since you only need two poles, route one leg back through the third OL pole so that the OL sees current on all three legs.

Tom

I optioned that already

As a solution we will try to put 2 heaters in serie to see if that works

Thanks
Peter

J_R_Thiele · Jan 13, 2022

OK, I will jump in and display my ignorance.

I looked up D/C motor inrush current, and found that this was several times the running current.

I looked up the overload relay, and it appears to be a thermal device.

You say the device trips "after some time". Is that with the motor under constant load, or is the motor stopping and starting? Any chance something on the motor end that increases its load to an overload after it has run a while?

Is there ventilation where the relay is located?

Peter from Holland · Jan 13, 2022

I measured less as 2 amps with a clamp on amp meter Running at different speeds or starting had little to no influence
Peter

TDegenhart · Jan 13, 2022

Where do you measure the current, a transformer style clamp ammeter will not respond to DC. If there is AC on the DC you will only see the AC component unless you have a ammeter with a Hall Effect sensor in it. Alternately, use an oscilloscope to see what is there. You can also check the current with a shunt and read the true RMS voltage to get the current.

Tom

Peter from Holland · Jan 13, 2022

The thermal overload is in the 220volts 50 hz supply line So that is where I measure
Peter

TDegenhart · Jan 13, 2022

All I can say is check the calibration of the ammeter and if it is accurate, then the only other possibility besides a defect relay is if the OL is in a high ambient environment.

Tom

Peter from Holland · Jan 14, 2022

We put the 2 heaters in serie and tested again After a much longer time as before it tripped once more
So it did have some effect at least
But.....
After further inspection we discovered that it was actualy set on 1.75 amps insted of the 2 we assumed The 2amp mark was lined up with another feature on the device

TDegenhart · Jan 15, 2022

When all else fails, check your assumptions.

Tom

rons · Jan 26, 2022

Peter from Holland said:
I have a contactor overload relay Telemecanique LR2 D13 1.6 to 2.5 Amp
It is protecting a 220 V 2Ph circuit board to drive a DC motor
We measure a load of 1.8 amps with a clamp on At least clearly below 2 amps
But setting the device at 2 amps it still trips after some time

Those rotary dials are not that accurate. And your meter is displaying averages not peak values.

If the trip happens after some time than it would not be because of phase loss. Your dial is set
too close to the line. Bump it up a bit on the adjustment dial and be happy the thing is trying to work for you.

Velisendderr · Nov 23, 2022

As it's a relevant thread so I wanna ask my question. Actually, I need three phase thermal overload relay and looking for best suggestions from you guys. Can I get it with these features:

1. 3 phase unbalance protection
2. Overload protection power failure protection and motor protection of it.
3. It should have stretching spring flip jumping mechanism.
4. flame-retardant housing
5. With CE certification

Can you pls guide me where I can buy this overload relay instead of Amazon?

Velisendderr · Nov 23, 2022

Velisendderr said:
As it's a relevant thread so I wanna ask my question. Actually, I need three phase thermal overload relay and looking for best suggestions from you guys. Can I get it with these features:

1. 3 phase unbalance protection
2. Overload protection power failure protection and motor protection of it.
3. It should have stretching spring flip jumping mechanism.
4. flame-retardant housing
5. With CE certification

Can you pls guide me where I can buy this overload relay instead of Amazon?

Thanks in advance for any suggestion.

Almost Retired · Dec 19, 2022

Velisendderr said:
Thanks in advance for any suggestion.

what is a "stretching spring flip jumping mechanism" ?

rons · Dec 20, 2022

Digi-Key
Mouser
Galco

I remember one or two members liking this on. You call call the 1-800 number and ask about it.

ICM450A and ICM450A+ - ICM CONTROLS

Programmable 3-Phase Line Voltage Monitors For more than two decades, ICM has been an innovator and a recognized leader in the manufacturer of line voltage controls designed to protect your most valuable equipment. The ICM450A and ICM450A PLUS+ are the latest 3-phase offerings, providing...

www.icmcontrols.com

jim rozen · Dec 20, 2022

"Does it only work properly with 3 ph connected ???"

Was this machine designed with this overload unit in place, or was it an add-on?

Overloads are supposed to trip of the rated current is at or near the trip level for an extended time. They're themally activated. Have you tried setting it to 2.25 amps or so, to see if that eliminates the issue?

Peter from Holland · Dec 20, 2022

jim rozen said:
"Does it only work properly with 3 ph connected ???"

Was this machine designed with this overload unit in place, or was it an add-on?

Overloads are supposed to trip of the rated current is at or near the trip level for an extended time. They're themally activated. Have you tried setting it to 2.25 amps or so, to see if that eliminates the issue?

Solved long ago like mentioned in my post 9

Peter

Almost Retired · Dec 20, 2022

Peter from Holland said:
Solved long ago like mentioned in my post 9

Peter

Jim, Ron and I were responding to a new question from Nov 23, 2022

Contactor Overload Relays on 2 phases

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