FYI: New Danfoss BD35/50 Control Module

[poiu]

Originally Posted by senormechanico

With FREE shipping.

I had in mind 10 cents. How much is a fuse or zener diode or capacitor?

[Richard Kollmann]

Rich, are you saying your Cubigel compressor modules are interchangeable with Danfoss modules? I though the module software was completely different.

[poiu]

Originally Posted by Richard Kollmann

Rich, are you saying your Cubigel compressor modules are interchangeable with Danfoss modules? I though the module software was completely different.

Richard, it was suggested above that you fix these things. Do you?

[Richard Kollmann]

No, to repairing modules. Rich, is correct I know of no one repairing them. I still test modules and you pay only shipping. There are four other small 12/24 volt less expensive compressor manufactures with electronic modules but I can only test Danfoss BD2, BD2.5, BD3, BD35 and BD50 modules.

[poiu]

Humph! It shouldn’t be like that.

[mrm]

Is there a 'typical' failure mode on these modules? Perhaps an underspecified component or lack of a fuse? Is there any modification which can be proactively done by EE skilled person to protect against failure?

[Richard Kollmann]

Short Module Serviceable Life can be caused by how refrigerator was installed.

Danfoss has always experienced problems with electronic control modules on BD compressors. After ten to fifteen different Danfoss module models still randomly failures occur with no warning. If we exclude lightening strikes and corrosion due to water module failures seem to be caused by voltage spikes or heat.

Voltage spikes at module are not always visible with a meter and can be present on any boat. Unstable voltage is why the module must receive power direct from battery buss using correct size wiring, fuses, circuit breaker and switches that allow no voltage drop. When compressor is correctly wired to battery buss battery will absorb voltage surges like a very large electrical capacitor reducing module electronics failures. When refrigerator is powered from a branch circuit breaker panel any item in that panel can cause a damaging voltage spike when that item is powered up or powered down. Any relay when power is turned off sends a voltage spike back towards the source. Windless, power wench, generator start relays and even cabin light relays can damage refrigerator control modules if refrigerator is wired through a circuit breaker panel instead of main buss.

Module overheating maybe the primary reason for so many electronic control module failures. Through the years Danfoss has designed static air heat sinks on modules to conduct and radiate heat away from transistors and other components inside module. Module heat increases as compressor load (amperage) increases. Danfoss’s installation application data sheets have always assumed system designers and installers would insure compressor design power amperage limits were not exceeded. What you will find in the marine industry is the elimination of module and compressor cooling air along with higher than design compressor heat loads. Only Danfoss’s AEO modules have built in module cooling fans. Danfoss’s variable speed specifications for BD50 require an additional fan for cooling control module if compressor is to be operated at maximum capacity (3500 rpm). All of the following conditions can cause module overheat failures; High condenser cooling temperatures, Repeated attempts to start do to an overloaded compressor, First box temperature pull down in a hot climate, System ambient temperatures above 105 degrees F, and too large or poorly designed holding plate evaporator coils. Failure to maintain good cool flow of condenser air, a normal maintenance item, should not be overlooked as cause of module failure.

[sailormed]

I found that on most "production boats" the fridge ventilation is nonexistant. On my Hunter 38 both fridge and freezer were totally lacking air in and out openings, resulting in overheating and continuous running of compressors in the summer. So I cut some air intake openings and forced air out fan holes.
I found a roughly 50% decrease in ampshours used in summer.
Below is a picture of the fridge fan opening. As usual, turn clockwise 90°.

[senormechanico]

Originally Posted by mrm

Is there a 'typical' failure mode on these modules? Perhaps an underspecified component or lack of a fuse? Is there any modification which can be proactively done by EE skilled person to protect against failure?

Several years ago, I repaired the module on my previous fridge.
It ate a couple FET transistors and emitter resistors.

No, I am NOT volunteering to be that guy.

[OzePete]

Yes, the 'Danfoss motor drivers (AKA electronic control modules) have been a major problem. Failure rates were always unacceptably high. and hugely expensive yet they had a good reputation!! (Hard to understand why!)
In my opinion as a refrigeration engineer, they were overpriced, over rated rubbish. We like others, had to use them as the options were few. Thankfully Danfoss stopped making compressors several years ago handing over to Secop who manufacturing in China and IMO they are now a far better product.

Regards the motor driver... they are particularly sensitive to voltage spikes and should have an external 'Voltage clamp, AKA Zorp or Transient Voltaqge Suppressor' fitted as standard so they could be protected against self destruction. They do have effective hi / low voltage cut out but that doesn't prevent spike damage. They also have high temperature and excess current draw protection etc so spikes were/ are the big killer. Another issue was corruption from a faulty fan. A defective fan powered via the motor driver supply can damage/ corrupt the motor driver. Best to power the fan(s) direct from DC supply via relay.
So, two things to protect your motor driver (and pocket!) Fit a voltage clamp and connect fan via a relay. This is what we do on all Ozefridge units and along with having used the soft start motor driver mentioned here for about the last three years, we can report a significant drop in motor driver faults.

The soft start is a major reason for vastly improved reliability as there is less stress/ damage as the start up doesn't involve a DOL whack of current. The driver we use has six stark soft start and the start current rate never exceeds the run rate. A beautiful piece of work!

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

[Typhoon]

Yes , protecting the controller you have is always the best option. The best system in the world is of no use if it is not working.

We also protect our units from voltage spikes and fan RF interference.

Regards John.

[ayates]

Originally Posted by OzePete

Regards the motor driver... they are particularly sensitive to voltage spikes and should have an external 'Voltage clamp, AKA Zorp or Transient Voltaqge Suppressor' fitted as standard so they could be protected against self destruction.

Originally Posted by ColdEh Marine

We also protect our units from voltage spikes and fan RF interference.

Notwithstanding this may be proprietary information, as anybody willing to share the specific clamping parts/circuits they use?


Thanks,

Allan.

[poiu]

Originally Posted by OzePete

Yes, the 'Danfoss motor drivers (AKA electronic control modules) have been a major problem. Failure rates were always unacceptably high. and hugely expensive yet they had a good reputation!! (Hard to understand why!)
In my opinion as a refrigeration engineer, they were overpriced, over rated rubbish. We like others, had to use them as the options were few. Thankfully Danfoss stopped making compressors several years ago handing over to Secop who manufacturing in China and IMO they are now a far better product.

Regards the motor driver... they are particularly sensitive to voltage spikes and should have an external 'Voltage clamp, AKA Zorp or Transient Voltaqge Suppressor' fitted as standard so they could be protected against self destruction. They do have effective hi / low voltage cut out but that doesn't prevent spike damage. They also have high temperature and excess current draw protection etc so spikes were/ are the big killer. Another issue was corruption from a faulty fan. A defective fan powered via the motor driver supply can damage/ corrupt the motor driver. Best to power the fan(s) direct from DC supply via relay.
So, two things to protect your motor driver (and pocket!) Fit a voltage clamp and connect fan via a relay. This is what we do on all Ozefridge units and along with having used the soft start motor driver mentioned here for about the last three years, we can report a significant drop in motor driver faults.

The soft start is a major reason for vastly improved reliability as there is less stress/ damage as the start up doesn't involve a DOL whack of current. The driver we use has six stark soft start and the start current rate never exceeds the run rate. A beautiful piece of work!

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

Do you supply the anti-surge suppressor? Or do you have a component reference so I can get one locally?

[Typhoon]

Originally Posted by ayates

Notwithstanding this may be proprietary information, as anybody willing to share the specific clamping parts/circuits they use?


Thanks,

Allan.

Hi Allan,

Send me a msg on our web site and I can send you out the items you need and how to install them .

Regards John.

[Richard Kollmann]

Pete, I do not know what manufacturers compressor you use in your Ozefreeze unit but Danfoss GmbH started in 1956 and did not go out of business only changed their name to Secop GmbH. They are still a leading manufacture of compressors.

Soft start modules are generally not requires on Danfoss compressors with conventional capillary tube refrigerant flow control.