The shorthand term for OCV Open Circuit Voltage. It is derived DC voltage present at the output terminal of a Welder. This voltage is typically average between 60-90 VDC at STICK (SMAW) mode of operation. The only exception to this (where the AC voltage is present) occurs when dealing with Transformer based STICK Welder (commonly called Buzz box) that has no DC improvement of the secondary transformer voltage. In another mode of operation (Weld processes) such as MIG (GMAW), or TIG (GTAW), the OCV will be different from that specified in STICK mode. Weld process is selected based on the Welder function. Not all Handyman capable of multiple processes. For example, a simple welder has STICK mode operation.
When the Problem Shooting SCR (Silicon Controlled Rectifier) Welder based, OCV measurements provide a valuable tool toward effective repair. The first step in this process is to consult Welders Service Manual. Specifications page will display the maximum OCV for the Weld selected. Record this voltage! Next, consult Scheme to reveal the number of SCR in the design, and the number of effective switching current path. Note the number of the current path! In this case, the current path is a branch of the secondary coils Transformers, via SCR (anode to cathode), and a peak into the current node before filtering the output inductor (reactor). Current node typically has several branches fed into it with a specific output.
Using a DVM (Digital Volt Meter) to measure the OCV of Welder. If close to the maximum OCV then this indicates that all SCR firing (triggered gating voltage is applied), and would be the ideal situation. If not, divide by the number of the Maximum OCV when activated. This amount is the voltage that each time the SCR or as part of the design. Subtract this value from the Maximum OCV. If the value (voltage) is equal to the voltage measured welder either SCR or the current path is broken. If not, continue this process for a number of road is currently being used.
An example of this is the Welder with 60V Maximum OCV is produced by simultaneously firing three SCR. The OCV is measured from the Welder is only 40V. 60 - (60/3) = 40. This would indicate a problem with either SCR or trigger problems. As you can see, the process is able to appoint Repair Technician for rapid fault resolution.
Until this point, the measurements have been taken (ie, OCV) occurs without opening the case welder. The following paragraphs refer to the component level Functional Test procedures. To move forward with this, the components (SCR, an IGBT or MOSFET) should be removed from the Welder suspects before performing this procedure. For security reasons, the situation must be electrically tested component is connected to other devices or power supplies other than Test Equipment used to identify defective components. If you are not experienced in Electronic Repair, and do not have a solid background of electricity does not try all kinds of electrical repairs on equipment type. In the Welder, there is high voltage present that can Kill. This warning is not to be taken lightly! In other words, if you are not qualified Electronics Technician, Electrical / Electronic Engineer or Electrician then treat this information as reference material only. View repairs to qualified specialists.
The SCR shall be tested individually out of the circuit utilizing SCR Tester or Component Analyzer. Type of Test Equipment capable of triggering Device-Under-Test. A DVM will not. Another important concern is the SCR ESD protection during the testing phase. Select the Hardware Test that the base (or connecting) all terminal SCR with the same potential as he completed the Functional Test. If there is no potential difference (voltage as a function of cost) between terminal SCR, there is the potential for ESD damage!
When problem-based Shooting an Inverter Welder, a low OCV usually indicates a problem with the welder IGBT Switching (Insulated Gate Bipolar Transistor) or MOSFET (Metal Oxide Semiconductor Field Effect Transistor). This is usually caused by faulty drivers or Gate Control Board. Both problems are solved by replacing the board, or component level repair.
When the OCV was measured at 0 VDC (and Welder were not blowing fuses or circuit breakers) Switching Components should be tested for function (Out-Of Circuit). An IGBT & MOSFET Tester or Component Analyzer should be used to perform this test. As with SCR Functional Test Procedures, DVM can not gate devices. But there are some exceptions to the test input capacitance gate MOSFET as high in some devices. Also, as stated earlier: DVM does not provide the level of ESD protection for the components while undergoing functional tests. If repair is attempted durable quality, ESD protection through a good selection of test equipment should be a major concern.
When the Problem Shooting SCR (Silicon Controlled Rectifier) Welder based, OCV measurements provide a valuable tool toward effective repair. The first step in this process is to consult Welders Service Manual. Specifications page will display the maximum OCV for the Weld selected. Record this voltage! Next, consult Scheme to reveal the number of SCR in the design, and the number of effective switching current path. Note the number of the current path! In this case, the current path is a branch of the secondary coils Transformers, via SCR (anode to cathode), and a peak into the current node before filtering the output inductor (reactor). Current node typically has several branches fed into it with a specific output.
Using a DVM (Digital Volt Meter) to measure the OCV of Welder. If close to the maximum OCV then this indicates that all SCR firing (triggered gating voltage is applied), and would be the ideal situation. If not, divide by the number of the Maximum OCV when activated. This amount is the voltage that each time the SCR or as part of the design. Subtract this value from the Maximum OCV. If the value (voltage) is equal to the voltage measured welder either SCR or the current path is broken. If not, continue this process for a number of road is currently being used.
An example of this is the Welder with 60V Maximum OCV is produced by simultaneously firing three SCR. The OCV is measured from the Welder is only 40V. 60 - (60/3) = 40. This would indicate a problem with either SCR or trigger problems. As you can see, the process is able to appoint Repair Technician for rapid fault resolution.
Until this point, the measurements have been taken (ie, OCV) occurs without opening the case welder. The following paragraphs refer to the component level Functional Test procedures. To move forward with this, the components (SCR, an IGBT or MOSFET) should be removed from the Welder suspects before performing this procedure. For security reasons, the situation must be electrically tested component is connected to other devices or power supplies other than Test Equipment used to identify defective components. If you are not experienced in Electronic Repair, and do not have a solid background of electricity does not try all kinds of electrical repairs on equipment type. In the Welder, there is high voltage present that can Kill. This warning is not to be taken lightly! In other words, if you are not qualified Electronics Technician, Electrical / Electronic Engineer or Electrician then treat this information as reference material only. View repairs to qualified specialists.
The SCR shall be tested individually out of the circuit utilizing SCR Tester or Component Analyzer. Type of Test Equipment capable of triggering Device-Under-Test. A DVM will not. Another important concern is the SCR ESD protection during the testing phase. Select the Hardware Test that the base (or connecting) all terminal SCR with the same potential as he completed the Functional Test. If there is no potential difference (voltage as a function of cost) between terminal SCR, there is the potential for ESD damage!
When problem-based Shooting an Inverter Welder, a low OCV usually indicates a problem with the welder IGBT Switching (Insulated Gate Bipolar Transistor) or MOSFET (Metal Oxide Semiconductor Field Effect Transistor). This is usually caused by faulty drivers or Gate Control Board. Both problems are solved by replacing the board, or component level repair.
When the OCV was measured at 0 VDC (and Welder were not blowing fuses or circuit breakers) Switching Components should be tested for function (Out-Of Circuit). An IGBT & MOSFET Tester or Component Analyzer should be used to perform this test. As with SCR Functional Test Procedures, DVM can not gate devices. But there are some exceptions to the test input capacitance gate MOSFET as high in some devices. Also, as stated earlier: DVM does not provide the level of ESD protection for the components while undergoing functional tests. If repair is attempted durable quality, ESD protection through a good selection of test equipment should be a major concern.
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Tagged @ Welder OCV
