Example of an Orphan Tracking System
Above: A dual-axis tracker made in central Ontario. This is the first production model. This picture was taken by me about 12 years ago. The company is no longer in business.
There are a number of trackers in Ontario that are no longer supported by the manufacturer and there is little to no installer support to keep them working. Most of these are dual axis trackers.
Deger trackers still supported
If you have a Deger dual axis tracker then parts are available, we stock the most commonly required parts and service these trackers for owners that can’t get service from the original installer. There are numerous installers that can service this brand of tracker.
If your tracker is not a Deger and it was installed in the early days of the microFIT program then you probably have an orphan tracker and may not know how to get it serviced. This document is intended to guide owners of orphaned trackers that are not working properly. It outlines what can be done to restore proper operation. Sonnen and Sentinel brands have exited the Candian market recently.
Support for Orphaned Brands of Trackers
Depending on the individual situation we may be able to provide you with suitable services. This may range from advice in this document to designing a custom solution that uses different parts and electronics from reliable sources. We would need at least one site visit to diagnose your problem.
There are two possible approaches when the problem is either failed electronics or a loss of configuration data that requires remote setup which no longer works. The first is to use all the electronics and sensors from Deger trackers to fix your system.
The 2nd and simpler and lower cost approach is to use a generic dual axis brightest spot tracking system built with European components. This can also be used for a single axis tracker.
Both of approaches will use the brightest object tracking approach, and does not need or use any internet connect or remote access. There is no software, the approach is purely hardware based.
Any brands such as Sonnen and Sentinel which use an astronomical tracking system will be converted to the simpler brightest spot tracking. The brightest spot tracking may not be as accurate on a cloudy day so this method is slightly less productive.
Deger is the only major manufacturer that is actively making dual axis trackers for the Ontario market and supplies replacement parts for their trackers. They also happen to be the manufacturer with the highest number of installed trackers since 1 Oct 2009 up to today. They have a sales & support office in Ontario. We can adapt their control electronics and sensors to work with other brands of trackers. However, using Deger parts is far more expensive than using a generic tracking controller, and will require more labour to install. The benefit is that there would be a ready source of parts, and there are dealers that know how to service problems with Deger electronic components.
What can be done if your tracker is no longer tracking the sun or won’t move manually?
There are four types of motors that could be used with solar trackers which are in order of most common to the least used type.
- Permanent magnet DC motor linear actuator for the elevation (tilt) axis and a permanent magnet DC motor to move the tracker in the East-West direction. These have 2 wires going to each motor.
- Stepper motor. These have 4-6 wires going to each motor. Currently we would require changing the 2 motors from a stepper motor to a permanent magnet DC motor for each axis. This type of motor is used on a astronomical control mechanism which can plot the course of the sun from any geographical location at a given time of the year.
- Brushless DC motor. These also have at least 3 wires connecting to each motor. If they have a built in controller that emulates a brushed DC motor then our electronics may support this type of motor.
- 120V or 240V 60 Hz AC induction motor. This is only used on very heavy trackers that require very powerful motors to move them.
Our electronics controller approach currently only supports type 1 motors. These are the vast majority of the motors used for trackers. The remainder of this page applies only to a tracker using a type 1 motor.
Control Electronics Problem:
To determine if the motors or the electronics are the problem, we disconnect the motors from the electronics and supply power from an external source and test if the motors operate and can move the tracker. If they can then the problem is confirmed to be with the control electronics. Then the approaches are:
- The simplest but least desirable solution is to disconnect the drive motors from its electronics and supply power from an external source and move the tracker to point due south and at a 30 to 45 degree tilt. Then leave it at this position. This should result in your generation of 75% of the power annually that it could generate when the tracker was working. This is the lowest cost service that can be done to improve upon tabletop mode or the tracker being stuck in a random position. This does leave it exposed to possible damage from high winds.
- This approach could be improved upon to add a seasonal tilt capability by improvising a manual motor control for the electric motor for the tilt axis (elevation). This could add up to about 5% more annual power generation relative to the previous case. This would also permit manual entering tabletop if a storm is expected.
- The best solution is to convert the tracker to using either Deger electronics and Deger MLD light sensors or our generic sensor and controller system to restore tracking operation. The complexity of this will vary and is more complex and expensive if the drive motors are not built to expect 24V DC to operate the motors. The complexity and cost increases if joystick manual control is required. If you wish to have a wind sensor and automatic entry into tabletop if the programmed wind speed is exceeded then another Deger module is required, also increasing the cost further. In the long term converting to either type of brightest spot tracking electronics is the most cost effective as it restores the energy capture to the maximum possible with your solar panels. It also enables future service of control electronics issues by using parts that are readily available.
Both of our electronics approaches expects that there will be limit switches to prevent the motors from moving too far. If the existing system does not have these built in, then a switch to replacement electronics will also require devising a system of 4 limit switches.
Elevation (Tilt) motor problem:
This type of motorized lead screw is referred to as a linear actuator. These need to handle a large amount of force when exposed to high wind speeds. What should be done if this linear actuator no longer works? It may be possible to find a replacement actuator. It should use the same motor drive voltage as the original actuator.
Temporarily, the tracker could be pointed due south and at a 30 to 45 degree tilt by turning the motor’s shaft manually if the actuator’s design permits manual rotation of the motor’s shaft. There may be an issue with the limit switches that may be built into some replacement actuators and not others.
It may be possible to use a Deger linear actuator. A custom mounting bracket may have to be designed and fabricated at a machine shop. The Deger electronics uses a DC Permanent magnet servo motor and built in adjustable limit switches as part of the actuator. Thus it could be used with the original electronics if it used limit switches.
East West Motor Problem:
First determine if the motor has failed or has the gearbox seized?
If the East-West motor has failed then find a replacement motor that uses the same voltage and is the same size. It may not be a standard size and therefore will be hard to locate. Generally, there is a greater chance of success of finding a suitable replacement for this motor rather than for the Elevation linear activator.
If the East-West gearbox is seized, (probably due to a lack of annual lubrication) what can be done? The fix for this is to replace the top of the tracker with an adaptor to change the mast size to fit the Deger’s mast top assembly. After all the panels have been removed a crane rental is required to take down the upper structure of the existing tracker, and then rebuild the upper part of the tracker starting with an adaptor to change the mast to fit Deger trackers. (Replacing everything except the base and mast) and rebuild as a Deger system and then re-install the solar panels on this top racking structure. This is by far the most expensive solution that might cost 1 year’s solar revenue.
Wind Sensor Problems
What if the system has a wind sensor (anemometer) and it no longer works? The most likely problem is that with time the bearings have worn out and the rotary cup does not turn as fast as it should and so under-reports the wind speed and thus it does not cause the tracker to move into tabletop position. It might wear enough that eventually it fails to turn.
If the sensor is operating but the control electronics has failed so that it ignores the wind sensor output, then a possible solution uses a Deger wind sensor and a DIN rail mounted Wind guard relay interface and couple this into the joystick or other manual positioning switch.
If the sensor has failed then the anemometer should be replaced.
- If a failed sensor uses a reed relay type of anemometer output with 2 pulses per turn, it could be replaced with the same model used by Deger.
- If the sensor uses a hall effect or analog output then a similar one would have to be located, which would take more time than just ordering a Deger Anemometer.
- As a last resort If the sensor output is either analog or a hall effect and no exact replacement can be found; it should be possible to use a Deger wind sensor and a DIN rail mounted Wind guard relay interface to couple this to the existing electronics.
Inverter or Panel Failure
Repairing either of these faults should not be any more difficult if the tracker is an orphaned product. As long as the tracker can be commanded to move this is no more difficult than doing the same repair on a supported tracker.
Inverter Failure
What if a string central inverter has failed? Replacing an inverter should not be a difficult task. It may not be the same brand of inverter but that should not matter. It will still generate the same amount of power.
What if a micro inverter(s) has failed? As long as it is an Enphase inverter then it should be possible to find an older model of microinverter. If not, then a newer model microinverter could be used. Here the issue is that Enphase has changed the A/C trunk cable a few times and a newer inverter will not fit the existing trunk cable connector. In this case some creative wiring may be required.
Panel Failure
What if one or more panels has stopped working? The panel could be replaced after the failed one(s) have been identified. The difficulty is getting a panel that has the same dimensions so that it can fit into the available space. This may take a while to find. In general, the mainstream panels have been getting bigger and have a higher wattage output rating. Replacing a panel requires 2 people to lift the panel into position. The homeowner can supply the extra person for a few minutes or I can supply the extra person which would be far more expensive.Tracker Structural Failure
There has been a structural failure that can’t be fixed or you have an east – west gearbox that has failed. We do not offer services to convert your entire tracker to using Deger parts or installing a new tracker or fixed ground mount, but we can provide good advice. Your choices are in order of descending cost:
- Install a new Deger dual axis tracker on top of your mast and re-use your existing panels. This restores your original annual production.
- Install a new Deger single axis S100-CF-DR tracker nearby and have a 5% drop in annual production. Note these are very long (23 meters) and so do not fit in the space of your original tracker which would be left in place. This could hold 44 panels, and would hold all the panels from two 5kW trackers or one 10kW tracker.
- Install a number of Deger 8.5 single axis trackers. These hold 4 panels each, so assuming the use of 250W panels available near the start of the microFIT program, you would have a total of 40 or more panels and would need 10 of these to replace a single 10kW tracker or 5 of these to replace one failed 5kW tracker. No heavy equipment is required to install these unless you use a precast concrete ballast foundation.
- Install a fixed ground mount racking system and have 75% of your original production for the failed tracker. Depending on your microFIT contract date and if you have a central string inverter you could install a few more panels to restore the original production. (After a specific contract version, you are not permitted to oversize your panels relative to your inverters.)