Motorised Blinds

[oli800]

Hi guys.

I have come into here to hope somone can help us.

We regularly fit out restaurants with 240v motorised blinds, however in 2 restaurants we have a problem

In both restaurants there are fused spurs which are for our blinds only.

In one restaurant we have 15 motors off 1 spur and the other we have 13.

Our motors are rated 116W and at 0.49A.

When all motors run, some will stop (and we call them stepping) and the others will carry on, but when we send a signal for them to begin again they close successfully.

We assume this is a power related problem, so are we overloading the spur?

Thanks

Oliver

 

[Sidewinder]

Welcome to the forum Oliver.

At 0.49A per motor full load current (yes?) you would not be overloading the FCU.

15x0.49A = 7.35A

However, how are these wired from the FCU out to the blind units, and in what size wiring?

 

[oli800]

Hi Sidewinder thanks for your quick reply.

I am unsure if it is the full load current, it states on the motor label it is 0.49A so I assume it will draw no higher than this?

We use 1.5mm 5 core cable from Neweys & Eyre, so I thought by using that, we would eliminate any issues.

Hope you can help.

Cheers

 

[Sidewinder]

OK, why 5 core?

1.5mm sq should be fine carrying up to 13A (the limit of an FCU).

I am presuming that this is a YY type flex?

How do you terminate the wiring?

I mean do you go from the FCU to a control box, then out to each blind?

Do you go from the FCU to the first blind, then loop on to the second, then the third etc.?

What is the length of run on the cable from the FCU to the furthest blind?

Is it the ones at the end of the run that are "failing"?

What is the voltage rating of the motors is it 240, or 220 to 250 or the like?

This will give an indication of the minimum voltage the motor will accept.

Is the control system a solid state electronic pack built in to the unit?

 

[IzzyS]

Hi guys.

I have come into here to hope somone can help us.

We regularly fit out restaurants with 240v motorised blinds, however in 2 restaurants we have a problem

In both restaurants there are fused spurs which are for our blinds only.

In one restaurant we have 15 motors off 1 spur and the other we have 13.

Our motors are rated 116W and at 0.49A.

When all motors run, some will stop (and we call them stepping) and the others will carry on, but when we send a signal for them to begin again they close successfully.

We assume this is a power related problem, so are we overloading the spur?

Thanks

Oliver

How are you sending the control signal?  Is it down one of the cores of the 5 core cable?  If you've combined control wiring with the power to the motors it may be interference on the control line causing the motor control unit(s) to turn off.

 

[oli800]

Hi Sidewinder,

Yes that is correct. We use a 5 core cable as 2 cables we use are for communication lines (BUS Lines). These send commands to the blinds from our home automation system which is a seperate box.

We go from the FCU to Wagobox 5, and then each blind is connected into a Wagobox 5 daisy chaining as you suggested correctly.

The voltage rating of the motor's are 230V-50Hz.

Not really does it happen on the end blinds, it can usuallty be the middle.

I wonder if the communication cable next to the live/earth/neutral is an issue?

How are you sending the control signal?  Is it down one of the cores of the 5 core cable?  If you've combined control wiring with the power to the motors it may be interference on the control line causing the motor control unit(s) to turn off.

Hi Izzy,

Yes just what I thought then. Why would it only do it on a selection of blinds though and not them all? It's strange!

 

[IzzyS]

If the automation kit signalling is SELV then it should really be separated from the power (LV) for safety and compliance with BS7671, as well as for avoidance of this problem. 

Could be any number of reasons why only some are affected - component tolerance, quality of manufacture, position on the wire (now acting as an incorrectly terminated transmission line for the induced noise), The only way to find out is to monitor the control lines with a 'scope and see what's happening.  Probably quicker and easier to run a separate screened control cable?

 

[Sidewinder]

What bus system is it?

Are you using the bus terminations correctly?

Is the cable characteristic correct for the bus topology?

However, these questions aside, IzzyS is probably correct.