1. Distinguish Two Types of Current
1. Steady-state standby input current (unit powered on standby mode)
2. Instant peak inrush current during exposure (maximum current at radiography, core factor for UPS selection)
Device: 50kW digital DR X-ray machine, 3-phase 380V input, power factor of high-voltage generator cosφ≈0.8
(1) Formula for Rated Steady-State Input Current
3-phase current calculation formula:
I = \frac{P}{\sqrt{3}×U×cosφ}
Parameters: P=50000W, U=380V, cosφ=0.8
(Designed for Grade A tertiary hospitals and upscale private clinics with higher price tags)
1. Siemens
Multix series high-power DR machines ranging from 50kW to 80kW. They boast top-tier stable high-voltage generators and extended X-ray tube service life.
2. Philips
DigitalDiagnost series standard 50kW general radiography units, equipped with premium image algorithms and optimized radiation emission control.
3. Fujifilm
FDR digital X-ray lineup with self-developed flat-panel detectors that deliver ultra-clear imaging, widely deployed in physical examination centers.
4. Canon (Former Toshiba Medical Systems)
DRX 50kW models feature lightweight build and a concise, user-friendly operation interface.
III. Supplementary Notes
1. 50kW is the standard power rating for general radiography; almost all certified formal DR manufacturers supply compatible models. The 65kW variant is an enhanced high-power version, engineered for radiography of obese patients and thick body parts.
2. For your Ghana market business, prioritize export-experienced brands: YSENMED, Sontu, Puai and Wandong. They provide readily available spare parts, verified UPS matching schemes and comprehensive after-sales support. Imported brands carry significant price premiums and see very few purchases from local clinics.
3. Power supply reminder: All 50kW models generate large inrush current during X-ray exposure. A 100kVA online UPS is universally recommended. Never use automotive starter batteries as energy storage batteries for this system
1. Distinguish Two Types of Current
1. Steady-state standby input current (unit powered on standby mode)
2. Instant peak inrush current during exposure (maximum current at radiography, core factor for UPS selection)
Device: 50kW digital DR X-ray machine, 3-phase 380V input, power factor of high-voltage generator cosφ≈0.8
(1) Formula for Rated Steady-State Input Current
3-phase current calculation formula:
I = \frac{P}{\sqrt{3}×U×cosφ}
Parameters: P=50000W, U=380V, cosφ=0.8
Calculated steady-state rated input current of the whole unit ≈95A
(2) Inrush Starting Current During Exposure (Critical Parameter)
The X-ray high-frequency switching high-voltage generator generates an inrush surge of 2~3 times the rated current at power-up and exposure, caused by capacitor charging and instantaneous high-voltage boost.
- Conservative surge multiplier: ×2.5 → Peak inrush current ≈237A
- Extreme surge multiplier: ×3 → Peak inrush current ≈285A
2. Supplementary: Internal Tube Current (High-Voltage Side, Not Mains Input)
For 50kW models, the maximum X-ray tube current is 630mA (under 150kV high voltage). This current flows inside the high-voltage circuit of the equipment and has no impact on front-end UPS and cable sizing; only the 380V mains input current is considered for power matching.
3. UPS Matching Logic
- 80kVA UPS: Rated 3-phase output current ≈122A
It can stably carry the 95A steady load, but has insufficient margin to withstand the 237A transient inrush surge.
- 100kVA UPS: Rated 3-phase output current ≈152A
Provides ample redundancy to sustain the 285A short pulse surge; 100kVA is the preferred option for medical applications.
Summary of Key Values
1. 3-phase 380V steady operating current of the unit: ~95A
2. Max instantaneous inrush starting current during exposure: 237~285A (duration: only several milliseconds)
3. Max internal high-voltage X-ray tube current: 630mA (irrelevant to mains power side)
