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I am going to make a conveyor like this

enter image description here

There will be a optic sensor which detects a box.

There will be motor (3 phase, 380 V, 1 A, 0.37 kW, 1400 rpm) with gear reduction (coefficient of reduction is 36). Power from this motor is enough for me.

The question is about the control and power systems.

My suggestion:

1) power line (3 phase) go to Schneider GV2ME08 (circuit breaker)

2) then go to Schneider lc1d09 (contactor)

3) then go to the motor.

Ic1d09 will be controlled with 24 AC. So I need transformer (220/24 AC)

I need a relay for commutating the 24 V.

This relay will be controlled with 5 V from Siemens Logo 24 RC. When the optic sensor sends a signal to the controller then this controller turns on the relay.

It is how do I see this picture.

My question: Is it correct? If it is correct does I can do it better? Will my conveyor do twitch? Do I need to use a frequency regulator for smooth start?

I will be glad for any opinion.

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    \$\begingroup\$ You have chosen all of the parts and given none of the measurable performance requirements \$\endgroup\$ – Sunnyskyguy EE75 May 22 at 21:17
  • \$\begingroup\$ The length of this table will be 245 cm. Maximum weight is 24 kg. The speed must be slow. But not very slow. I can not say exactly which speed I need \$\endgroup\$ – Salekh May 23 at 2:51
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    \$\begingroup\$ I was expecting important metrics like acceleration, velocity, interface requirements, sound level, available power sources, budget, and reasons for choices. \$\endgroup\$ – Sunnyskyguy EE75 May 23 at 3:45
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Selection components to control a 3 phase motor/conveyer

The components you selected are adequate for the load you specify.

The Schneider lc1d09 contactor has adequate load capability. I would strongly suggest that you use the 24V AC coil (or the 110V AC coil) to ease your wiring since you appear not to be using a DIN enclosure.

To drive the contactor you will need a Class 105/106 rated control transformer.
Here is an example that might be suitable for phase to neutral connection:

enter image description here

This allows your wiring closet to be only AC mains equipment.

To setup your optical curtain you need to select a device of course, and should get a floating relay output for either 24 or 120V AC rating (most will easily do this. This will probably be a low voltage 12 or 24V DC operation and kept separate from your motor wiring.

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  • \$\begingroup\$ Thank you! I did not know about this class transformers. \$\endgroup\$ – Salekh May 23 at 2:41
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Usually the photocells and other proximity sensors work on 24 VDC. In my opinion, you should change to 24DC power supply and use a contactor for 24VDC.

In any case do not forget to order a contactor with built-in suppressor device, this can be a MOV or a diode. MOVs are more universal in this case.

Your conveyor will start with high acceleration, 95% is good enough for any use, in only few cases you'd need a frequency converter.

EDIT: You don't even need to supply the contactor with 24VAC or DC, you can use 220VAC contactor and use the output relay of Logo to switch it on.

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    \$\begingroup\$ @Marla Replaced IMO with: In my opinion. \$\endgroup\$ – Marko Buršič May 22 at 21:36
  • \$\begingroup\$ So if I understand correctly. In your suggestion connector's coil is controlled with 220 VAC. It looks very nice because in your scenario I need not reley. But how I can turn on 220 VAC coil dirrectly from Logo without reley? \$\endgroup\$ – Salekh May 23 at 2:30
  • \$\begingroup\$ The logo itself has output relays, if it is marked with R - Relay output. \$\endgroup\$ – Marko Buršič May 24 at 19:38
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does it correct? If it is correct does I can do it better?

The selected components seem correct with improvements recommended in other answers.

You should review the thermal trip setting range of the Schneider GV2ME08. The minimum of the setting range should be no higher than the motor current rating.

Will my conveyor do twitch? Do I need use frequency regulator for smooth start?

The conveyor will probably accelerate to full speed in about a second. That may see quite sudden, but relatively smooth. The need for a frequency regulator, variable frequency drive (VFD), will be determined by the sensitivity of the load. Most such conveyors don't require a VFD, but the need will be difficult to predict.

You should also consider how often the conveyor will be started and stopped. You need to define the action of the conveyor in detail and be sure that you don't need more that the one sensor to get the desired action.

Circuit Breaker Selection and Setting

Based on the table and curves below, I would select the GV2ME05 and set the trip slightly below the maximum setting. The GV2ME06 might be ok with the setting at minimum.

The magnetic trip allows about 15 X setting current. The thermal trip allows 15 X setting current for about 0.7 to 2 seconds and trips in about 10 to 50 seconds at 2 X setting current. The thermal mechanism will not trip below about 1.25 X the setting current. I believe the setting should be at the motor rated current or even slightly below to assure protection from long-term overload or excessive starting and stopping.

enter image description here

enter image description here

Added Information

The conveyor speed can be calculated from known gear ratio and the main roll diameter. Tomato boxes may slip a little when the conveyor starts, but it seems very unlikely that they would tip over. The acceleration force in unlikely to bruise the tomatoes.

At 1400 RPM, the motor has higher slip than average. The maximum starting current will be less than average. The starting torque will be maximum at standstill and drop steadily as the motor accelerates. The motor has been selected for full-voltage starting, not for use with a VFD.

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  • \$\begingroup\$ The minimum setting should be just higher than the surge requirements of the motor or you will get unintended trips if the belt starts with considerable load on it. \$\endgroup\$ – Jack Creasey May 23 at 0:46
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    \$\begingroup\$ @Jack Creasey: See my revised answer. \$\endgroup\$ – Charles Cowie May 23 at 1:31
  • \$\begingroup\$ Thank you! I will note your answer. This conveyor is 250 cm long. Maximum load will be 24 kg ( 4 boxes with 6 kg each). I hope I need not VFD. Because on final stage there are will be the same 4 tables \$\endgroup\$ – Salekh May 23 at 2:39
  • \$\begingroup\$ The load is a tomato. So this twitch will be not dangerous maybe. Yes? \$\endgroup\$ – Salekh May 23 at 2:55
  • \$\begingroup\$ See revised answer. The question should be revised to include the information added in comments. \$\endgroup\$ – Charles Cowie May 23 at 12:25

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