Medical Isolation Transformer
Tortech has a vast experience of designing toroidal transformers to meet the requirements of IEC 601 and UL 544.
The most important aspects of designing a transformer to UL 544 requirements are construction, leakage current, and abnormal operation as defined in UL 544 sections 19, 27, and 41, respectively. Unless the customer dictates otherwise, we use construction called out in paragraphs 19.4C or E of UL 544. These are for patient-care equipment. Paragraph C is satisfied by using a grounded copper shield between primaries and secondaries in combination with a thermal protection device. Often, our customers prefer this type of construction because the copper shield is considered a failsafe protection against electrical shock. However, this approach adds cost and may be unnecessary.
A more economical approach is construction per paragraph E, which is satisfied by using a thermal protection device in combination with three layers of insulating material, of which any combination of two layers are capable of withstanding a 3,500 volt 60 Hz dielectric test potential for one minute.
Leakage current is that current which can be conducted through the patient’s body if the protective ground to the wall power cord is broken. Toroidal transformers can contribute leakage current through two paths: from primary to secondary, and from primary to mounting surface. Drawing on years of experience, our engineers can design toroidal transformers and mounting techniques that will minimize the transformer’s contribution to system leakage. However, the equipment designer must also account for other components within the system that will contribute leakage current such as power cords, switches, line filters, and fuse holders.
Tortech can measure leakage current with a tester constructed to the circuit in UL 544 figure 24.1 and section 27.5, at the customer”s request.
Section 34 of UL 544 describes tests to which the transformer will be subjected in order to confirm that abnormal operation (which the system may encounter in actual service) will not present a shock or fire hazard to the patient or operator. Equipment designers should investigate the possible abnormal tests UL may perform on their particular system, then contact Tortech engineers for assistance in creating the transformer specifications. Working together with our engineers as a team, designers can be assured of accurate, functional transformers without multiple iterations, thereby cutting development costs.
Test Report note: Tortech can offer routine test report to show compliance with the Medical Standard IEC 601.1. (not a type test report).
Tortech equipment is fully calibrated to IEC 601.1 Medical testing equipment. Standard /When the product is ordered if the customer wants IEC 601.1 routine test report the extra charge is $100 +GST per type.
Tortech does not have full compliance to IEC 601.1 for all the range of medical transformer that it sells it that medical transformer only sold in small quantity and there is vast variation of products and models. The electrical permutation and medical combination available are very large. Hence the cost of IEC 601.1 compliance is price prohibitive.
500W, 1000W, 2000W