What is the function of a PTC?
The PTC protects the start winding by switching it off.
When can a PTC be used?
A compressor can be started using a PTC if the appliance has a standstill period of minimally 7 minutes in order to ensure pressure equalization via the capillary tube.
Will the wiring in the compressor automatically fail when the PTC starting device burns out? Can the compressor be ohmed out to check for shortings?
Generally the compressor should be still okay even if the PTC starting device burns out - we recommend using a new PTC instead.
The nominal values for the main winding and for the start winding at a temperature of 25 °C are stated in the data sheet. Depending on the actual ambient temperature this nominal value has to be corrected by a factor from the following table.
t / °C
t / °F
Example: For the NL7CNK compressor the value given in the data sheet is 14.7 Ohm @ 25 °C. If your ambient temperature is 40 °C, you have to multiply this by 1.058 as declared in the table. So your resistance would be 1.058 x 14.7 Ohm = 15.6 Ohm.
Please note that these values apply only if the resistance is measured directly at the stator - you should include a tolerance of about +/- 10 %.
What is the advantage of an ePTC?
The main advantage of the ePTC solution is the easy way of saving energy in existing and future fridge and freezer designs.
This is due to the following factors:
- Reduction of 2 W in power consumption
- Full PTC protection of start winding
- Can be operated with a run capacitor
- Silent operation
- Short recovery time
- Compatibility to all Secop 103N PTC starters
In special cases, an ePTC can replace a PTC/run capacitor combination.
What does the stamping on a capacitor mean, e.g.: AC 220V 1.7% ED SD=3MIN AC 280V 0.55% ED SD=1MIN
In this example, the capacitor can operate at 220 V AC for a maximum time of 1.7 % within 3 minutes. More exactly, this means the capacitor should be operated for maximum of 3.1 seconds and afterwards be off for 176.9 seconds.
At 280 V AC, the capacitor can be used for 0.3 seconds in a period of one minute.
Can capacitors with a different rating than specified in your literature be used?
Yes, that is possible. The voltage rating of all capacitors must be the same as, or higher than, the specified voltage.
Can I replace the standard run capacitor delivered by Secop with another type having the same electrical data but with safety class P0?
For safety reasons Secop only distributes run capacitors of safety class P2 (with aluminum housing) instead of safety class P0 (with plastic housing) with its compressors.A P0 run capacitor is normally not used by e.g. German manufacturers because of safety and insurance reasons. On the other hand we know that P0 run capacitors are used by several manufacturers elsewhere.If using a P0 run capacitor it is very important to follow the instructions from the supplier regarding safety conception to prevent any fire in case the not protected flammable capacitor fails - e.g. distance to flammable parts should be at least 100 mm or the capacitor should be encapsulated. So when technical matters are ok on the P0 capacitor we cannot see why it should not be operated with a Secop compressor. Also, please consider that probably the Secop run capacitor holder will not fit the capacitor. Since in this way it can not be installed directly on the compressor housing, a compact installation incl. earth connection can not be ensured.
Can existing starting equipment be used with another compressor?
Generally no, it can not.The Secop Engineering Department has selected optimised starting equipment for each compressor which meets the requirements and specifications. We therefore strongly advise using only the starting equipment that is recommended by Secop.Especially when using starting relays, the cut-in- and cut-out current values have to match the motor requirements precisely. A wrong relay can destroy the motor or the start capacitor and cause severe safety problems.
Does the designation "198V-254V" state the start voltage range or the working voltage range?
When we state a voltage range of 198V - 254V in our catalogues, it means that the compressor can both run and start at voltages within this range.
What does "Minimum circuit ampacity xx" mean?
The term "ampacity" is a combination of "amperage" and "capacity".
The formula for the calculation of the ampacity is: RLA (rated load amps) of the compressor added to FLA (full load amps) of the fan multiplied with 1.25 (safety factor).
The ampacity defines the maximum current that can occur when the compressor is running at the highest specified load and a higher voltage than given.
Can Secop recommend substitutes for failing compressors in old appliances
Example: A cooler from 1977 is equipped with a PW7.5K14 compressor. For several months the compressor ran longer and longer and finally worked continuously. Since the thermostat is operational, it is probable that the compressor has reached the end of its lifecycle. Is there be an appropriate substitute?
No, Secop will not recommend substitutes for failing old devices.
When after ten or more years of use a compressor in an appliance finally fails, it can not be recommended to replace it even if it was technically feasible. After ten or more years of use, the insulation and the sealing of a refrigerator and freezer are used up. This would lead to significantly increased energy consumption.
Furthermore, the refrigerant R12 is no longer allowed in most countries. Replacing it with another refrigerant will become quite expensive.
The sensible recommendation is to buy a new appliance.
What is the recommended position to transport a refrigerator horizontally over a short distance?
The allowed positions of each compressor type are stated in the according Product Bulletin – Shipment of Refrigeration Appliances in horizontal Position.
If the unit has been shipped in a correct position according to the Technical Information we recommend waiting for another 30 minutes before switching on the refrigerator.
Is the refrigerator ready to run once it is returned to the upright position or should it rest for a certain period of time before it is turned on?
For allowed positions of each compressor type please check the Product Bulletins – Shipment of Refrigeration Appliances in horizontal Position.
If the unit has been transported in a correct position according to the technical information we recommend waiting for another 30 minutes before switching the refrigerator on.
What is the difference between the standard compressor and the tropical compressor?
There are two main differences between the tropical compressor and the corresponding standard compressor:
- All tropical compressors can be operated at a maximum ambient temperature of 43°C while most standard compressors are designed to work at temperatures up to 38°C.
- While the tropical compressors can be operated at a voltage range from 187 - 254 V, the corresponding standard compressors have a smaller range of 198 - 254V.
These factors require the tropical compressors to be equipped with a stronger motor which slightly decreases the COP.
Do you make a compressor that would be able to use a refrigerant like R23 with POE oil or R13 with mineral oil for the low stage of a cascade system?
Secop compressors are available for R12, R22, R134a, R290, R404A, R407C, R502, R507, or R600a applications. We have no experience with compressors used with other refrigerants or used in cascade applications at very low temperatures. We know that some customers use the compressors with other refrigerants, but we have not been involved in any testing or approval for such applications and / or system layouts.
If a compressor is used for any such special application (on own risk) it is recommended that the load conditions do not exceed the equal maximum load conditions of the refrigerant the compressor is designed for. General Information on the operating conditions can be found in the relevant catalogue, more specific on the data sheet of the compressor.
There are no datasheets for R12 or R22 compressor in the datasheet selector.
We don't have the datasheets of our older compressor and condensing
unit types on our website, but we will gladly send you the
documentation by mail or e-mail on request.
Can I use a leak detection dyes in refrigeration systems?
Secop does not endorse the use of any substance except the refrigerant and the oil designed for use in the specific compressor.
Can ammonia be used as a refrigerant in a Secop compressor if combined with a compatible oil? Does Secop have any experience with the use of ammonia in hermetic compressors?
No, it can not.
All Secop hermetic compressors use motor windings of enamel copper wire, and some other small parts of copper or copper alloys. The copper will be attacked by ammonia, so the compressors will certainly be damaged.
All materials used for the internal parts of Secop compressors are only tested for chemical compatibility with the oils and refrigerants they are made for. Changing the oil, maybe even changing the producer of the oil might lead to problems.
Ammonia generally is not used in small hermetic systems because ammonia develops very high temperatures when compressed.
At what speed do Secop hermetic compressors run?
On 50 Hz supply the compressors nominally run at 2900 rpm while at 60 Hz the nominal speed is 3450 rpm.